Nanomaterials

19 pages, 4885 KiB

Open AccessEditor’s ChoiceArticle

TiO₂ Nanoparticles with Adjustable Phase Composition Prepared by an Inverse Microemulsion Method: Physicochemical Characterization and Photocatalytic Properties

by Bogna D. Napruszewska, Anna Walczyk, Dorota Duraczyńska, Joanna Kryściak-Czerwenka, Robert Karcz, Adam Gaweł, Paweł Nowak and Ewa M. Serwicka

Nanomaterials 2024, 14(13), 1130; https://doi.org/10.3390/nano14131130 - 30 Jun 2024

Viewed by 615

Abstract

Titania nanoparticles (NPs) find wide application in photocatalysis, photovoltaics, gas sensing, lithium batteries, etc. One of the most important synthetic challenges is maintaining control over the polymorph composition of the prepared nanomaterial. In the present work, TiO₂ NPs corresponding to anatase, rutile, [...] Read more.

Titania nanoparticles (NPs) find wide application in photocatalysis, photovoltaics, gas sensing, lithium batteries, etc. One of the most important synthetic challenges is maintaining control over the polymorph composition of the prepared nanomaterial. In the present work, TiO₂ NPs corresponding to anatase, rutile, or an anatase/rutile/brookite mixture were obtained at 80 °C by an inverse microemulsion method in a ternary system of water/cetyltrimethylammonium bromide/1-hexanol in a weight ratio of 17:28:55. The only synthesis variables were the preparation of the aqueous component and the nature of the Ti precursor (Ti(IV) ethoxide, isopropoxide, butoxide, or chloride). The materials were characterized with X-ray diffraction, scanning/transmission electron microscopy, N₂ adsorption–desorption isotherms, FTIR and Raman vibrational spectroscopies, and diffuse reflectance spectroscopy. The synthesis products differed significantly not only in phase composition, but also in crystallinity, textural properties, and adsorption properties towards water. All TiO₂ NPs were active in the photocatalytic decomposition of rhodamine B, a model dye pollutant of wastewater streams. The mixed-phase anatase/rutile/brookite nanopowders obtained from alkoxy precursors showed the best photocatalytic performance, comparable to or better than the P25 reference. The exceptionally high photoactivity was attributed to the advantageous electronic effects known to accompany multiphase titania composition, namely high specific surface area and strong surface hydration. Among the single-phase materials, anatase samples showed better photoactivity than rutile ones, and this effect was associated, primarily, with the much higher specific surface area of anatase photocatalysts. Full article

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14 pages, 3793 KiB

Open AccessEditor’s ChoiceArticle

Energy Storage Application of CaO/Graphite Nanocomposite Powder Obtained from Waste Eggshells and Used Lithium-Ion Batteries as a Sustainable Development Approach

by Kathalingam Adaikalam, Aviraj M. Teli, Karuppasamy Pandian Marimuthu, Sivalingam Ramesh, Hyungyil Lee, Heung Soo Kim and Hyun-Seok Kim

Nanomaterials 2024, 14(13), 1129; https://doi.org/10.3390/nano14131129 - 30 Jun 2024

Viewed by 636

Abstract

The reuse of waste materials has recently become appealing due to pollution and cost reduction factors. Using waste materials can reduce environmental pollution and product costs, thus promoting sustainability. Approximately 95% of calcium carbonate-containing waste eggshells end up in landfills, unused. These eggshells, [...] Read more.

The reuse of waste materials has recently become appealing due to pollution and cost reduction factors. Using waste materials can reduce environmental pollution and product costs, thus promoting sustainability. Approximately 95% of calcium carbonate-containing waste eggshells end up in landfills, unused. These eggshells, a form of bio-waste, can be repurposed as catalytic electrode material for various applications, including supercapacitors, after being converted into CaO. Similarly, used waste battery electrode materials pose environmental hazards if not properly recycled. Various types of batteries, particularly lithium-ion batteries, are extensively used worldwide. The recycling of used lithium-ion batteries has become less important considering its low economic benefits. This necessitates finding alternative methods to recover and reuse the graphite rods of spent batteries. Therefore, this study reports the conversion of waste eggshell into calcium oxide by high-temperature calcination and extraction of nanographite from spent batteries for application in energy storage fields. Both CaO and CaO/graphite were characterized for their structural, morphological, and chemical compositions using XRD, SEM, TEM, and XPS techniques. The prepared CaO/graphite nanocomposite material was evaluated for its efficiency in electrochemical supercapacitor applications. CaO and its composite with graphite powder obtained from used lithium-ion batteries demonstrated improved performance compared to CaO alone for energy storage applications. Using these waste materials for electrochemical energy storage and conversion devices results in cheaper, greener, and sustainable processes. This approach not only aids in energy storage but also promotes sustainability through waste management by reducing landfills. Full article

(This article belongs to the Special Issue Application of Nanomaterials as Catalysts for Energy Storage and Conversion)

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9 pages, 542 KiB

Open AccessEditor’s ChoiceArticle

Random Field Ising Model Criticality in a Complex Binary Liquid System

by Henrich Frielinghaus, Purushottam S. Dubey, Debasish Saha, Eunjoo Shin, Olaf Holderer, Jan V. Sengers and Stephan Förster

Nanomaterials 2024, 14(13), 1125; https://doi.org/10.3390/nano14131125 - 29 Jun 2024

Viewed by 547

Abstract

While Ising criticality in classical liquids has been firmly established both theoretically and experimentally, much less is known about criticality in liquids in which the growth of the correlation length is frustrated by finite-size effects. A theoretical approach for dealing with this issue [...] Read more.

While Ising criticality in classical liquids has been firmly established both theoretically and experimentally, much less is known about criticality in liquids in which the growth of the correlation length is frustrated by finite-size effects. A theoretical approach for dealing with this issue is the random-field Ising model (RFIM). While experimental critical-exponent values have been reported for magnetic samples (here, we consider

γ

,

ν

and

η

), little experimental information is available for critical fluctuations in corresponding liquid systems. In this paper, we present a study on a binary liquid consisting of 3-methyl pyridine and heavy water in a very light-weight porous gel. We find that the experimental results are in agreement with the theoretical predictions from the RFIM. Full article

(This article belongs to the Topic Multifunctional Porous Materials: Preparation, Structure, Modeling and Applications)

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22 pages, 2160 KiB

Open AccessEditor’s ChoiceReview

Advancements in Aerogel Technology for Antimicrobial Therapy: A Review

by George-Alexandru Croitoru, Diana-Cristina Pîrvulescu, Adelina-Gabriela Niculescu, Marius Rădulescu, Alexandru Mihai Grumezescu and Carmen-Larisa Nicolae

Nanomaterials 2024, 14(13), 1110; https://doi.org/10.3390/nano14131110 - 28 Jun 2024

Viewed by 652

Abstract

This paper explores the latest advancements in aerogel technology for antimicrobial therapy, revealing their interesting capacity that could improve the current medical approaches for antimicrobial treatments. Aerogels are attractive matrices because they can have an antimicrobial effect on their own, but they can [...] Read more.

This paper explores the latest advancements in aerogel technology for antimicrobial therapy, revealing their interesting capacity that could improve the current medical approaches for antimicrobial treatments. Aerogels are attractive matrices because they can have an antimicrobial effect on their own, but they can also provide efficient delivery of antimicrobial compounds. Their interesting properties, such as high porosity, ultra-lightweight, and large surface area, make them suitable for such applications. The fundamentals of aerogels and mechanisms of action are discussed. The paper also highlights aerogels’ importance in addressing current pressing challenges related to infection management, like the limited drug delivery alternatives and growing resistance to antimicrobial agents. It also covers the potential applications of aerogels in antimicrobial therapy and their possible limitations. Full article

(This article belongs to the Special Issue Advances in Bioactive Nanoparticles on Wound Healing, Tissue Engineering and Drug Delivery)

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21 pages, 6750 KiB

Open AccessEditor’s ChoiceArticle

A Hierarchical Nano to Micro Scale Modelling of 3D Printed Nano-Reinforced Polylactic Acid: Micropolar Modelling and Molecular Dynamics Simulation

by AbdolMajid Rezaei, Razie Izadi and Nicholas Fantuzzi

Nanomaterials 2024, 14(13), 1113; https://doi.org/10.3390/nano14131113 - 28 Jun 2024

Viewed by 533

Abstract

Fused deposition modelling (FDM) is an additive manufacturing technique widely used for rapid prototyping. This method facilitates the creation of parts with intricate geometries, making it suitable for advanced applications in fields such as tissue engineering, aerospace, and electronics. Despite its advantages, FDM [...] Read more.

Fused deposition modelling (FDM) is an additive manufacturing technique widely used for rapid prototyping. This method facilitates the creation of parts with intricate geometries, making it suitable for advanced applications in fields such as tissue engineering, aerospace, and electronics. Despite its advantages, FDM often results in the formation of voids between the deposited filaments, which can compromise mechanical properties. However, in some cases, such as the design of scaffolds for bone regeneration, increased porosity can be advantageous as it allows for better permeability. On the other hand, the introduction of nano-additives into the FDM material enhances design flexibility and can significantly improve the mechanical properties. Therefore, modelling FDM-produced components involves complexities at two different scales: nanoscales and microscales. Material deformation is primarily influenced by atomic-scale phenomena, especially with nanoscopic constituents, whereas the distribution of nano-reinforcements and FDM-induced heterogeneities lies at the microscale. This work presents multiscale modelling that bridges the nano and microscales to predict the mechanical properties of FDM-manufactured components. At the nanoscale, molecular dynamic simulations unravel the atomistic intricacies that dictate the behaviour of the base material containing nanoscopic reinforcements. Simulations are conducted on polylactic acid (PLA) and PLA reinforced with silver nanoparticles, with the properties derived from MD simulations transferred to the microscale model. At the microscale, non-classical micropolar theory is utilised, which can account for materials’ heterogeneity through internal scale parameters while avoiding direct discretization. The developed mechanical model offers a comprehensive framework for designing 3D-printed PLA nanocomposites with tailored mechanical properties. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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13 pages, 2347 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Ultra-Mild Fabrication of Highly Concentrated SWCNT Dispersion Using Spontaneous Charging in Solvated Electron System

by Junho Shin, Jung Hoon Kim, Jungeun Lee, Sangyong Lee, Jong Hwan Park, Seung Yol Jeong, Hee Jin Jeong, Joong Tark Han, Seon Hee Seo, Seoung-Ki Lee and Jungmo Kim

Nanomaterials 2024, 14(13), 1094; https://doi.org/10.3390/nano14131094 - 26 Jun 2024

Viewed by 914

Abstract

The efficient dispersion of single-walled carbon nanotubes (SWCNTs) has been the subject of extensive research over the past decade. Despite these efforts, achieving individually dispersed SWCNTs at high concentrations remains challenging. In this study, we address the limitations associated with conventional methods, such [...] Read more.

The efficient dispersion of single-walled carbon nanotubes (SWCNTs) has been the subject of extensive research over the past decade. Despite these efforts, achieving individually dispersed SWCNTs at high concentrations remains challenging. In this study, we address the limitations associated with conventional methods, such as defect formation, excessive surfactant use, and the use of corrosive solvents. Our novel dispersion method utilizes the spontaneous charging of SWCNTs in a solvated electron system created by dissolving potassium in hexamethyl phosphoramide (HMPA). The resulting charged SWCNTs (c-SWCNTs) can be directly dispersed in the charging medium using only magnetic stirring, leading to defect-free c-SWCNT dispersions with high concentrations of up to 20 mg/mL. The successful dispersion of individual c-SWCNT strands is confirmed by their liquid-crystalline behavior. Importantly, the dispersion medium for c-SWCNTs exhibits no reactivity with metals, polymers, or other organic solvents. This versatility enables a wide range of applications, including electrically conductive free-standing films produced via conventional blade coating, wet-spun fibers, membrane electrodes, thermal composites, and core-shell hybrid microparticles. Full article

(This article belongs to the Special Issue Preparation, Separation, Characterization and Application of Carbon Nanotubes)

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16 pages, 3821 KiB

Open AccessEditor’s ChoiceArticle

Development of Focused Ultrasound-Assisted Nanoplexes for RNA Delivery

by Sanjeev Ranjan, Stef Bosch, Hannamari Lukkari, Johanna Schirmer, Niina Aaltonen, Heikki J. Nieminen, Vesa-Pekka Lehto, Arto Urtti, Tatu Lajunen and Kirsi Rilla

Nanomaterials 2024, 14(13), 1089; https://doi.org/10.3390/nano14131089 - 25 Jun 2024

Viewed by 1060

Abstract

RNA-based therapeutics, including siRNA, have obtained recognition in recent years due to their potential to treat various chronic and rare diseases. However, there are still limitations to lipid-based drug delivery systems in the clinical use of RNA therapeutics due to the need for [...] Read more.

RNA-based therapeutics, including siRNA, have obtained recognition in recent years due to their potential to treat various chronic and rare diseases. However, there are still limitations to lipid-based drug delivery systems in the clinical use of RNA therapeutics due to the need for optimization in the design and the preparation process. In this study, we propose adaptive focused ultrasound (AFU) as a drug loading technique to protect RNA from degradation by encapsulating small RNA in nanoliposomes, which we term nanoplexes. The AFU method is non-invasive and isothermal, as nanoplexes are produced without direct contact with any external materials while maintaining precise temperature control according to the desired settings. The controllability of sample treatments can be effectively modulated, allowing for a wide range of ultrasound intensities to be applied. Importantly, the absence of co-solvents in the process eliminates the need for additional substances, thereby minimizing the potential for cross-contaminations. Since AFU is a non-invasive method, the entire process can be conducted under sterile conditions. A minimal volume (300 μL) is required for this process, and the treatment is speedy (10 min in this study). Our in vitro experiments with silencer CD44 siRNA, which performs as a model therapeutic drug in different mammalian cell lines, showed encouraging results (knockdown > 80%). To quantify gene silencing efficacy, we employed quantitative polymerase chain reaction (qPCR). Additionally, cryo-electron microscopy (cryo-EM) and atomic force microscopy (AFM) techniques were employed to capture images of nanoplexes. These images revealed the presence of individual nanoparticles measuring approximately 100–200 nm in contrast with the random distribution of clustered complexes observed in ultrasound-untreated samples of liposome nanoparticles and siRNA. AFU holds great potential as a standardized liposome processing and loading method because its process is fast, sterile, and does not require additional solvents. Full article

(This article belongs to the Section Biology and Medicines)

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28 pages, 10260 KiB

Open AccessEditor’s ChoiceReview

Carbon-Enhanced Hydrated Salt Phase Change Materials for Thermal Management Applications

by Yizhe Liu, Xiaoxiang Li, Yangzhe Xu, Yixuan Xie, Ting Hu and Peng Tao

Nanomaterials 2024, 14(13), 1077; https://doi.org/10.3390/nano14131077 - 24 Jun 2024

Viewed by 731

Abstract

Inorganic hydrated salt phase change materials (PCMs) hold promise for improving the energy conversion efficiency of thermal systems and facilitating the exploration of renewable thermal energy. Hydrated salts, however, often suffer from low thermal conductivity, supercooling, phase separation, leakage and poor solar absorptance. [...] Read more.

Inorganic hydrated salt phase change materials (PCMs) hold promise for improving the energy conversion efficiency of thermal systems and facilitating the exploration of renewable thermal energy. Hydrated salts, however, often suffer from low thermal conductivity, supercooling, phase separation, leakage and poor solar absorptance. In recent years, compounding hydrated salts with functional carbon materials has emerged as a promising way to overcome these shortcomings and meet the application demands. This work reviews the recent progress in preparing carbon-enhanced hydrated salt phase change composites for thermal management applications. The intrinsic properties of hydrated salts and their shortcomings are firstly introduced. Then, the advantages of various carbon materials and general approaches for preparing carbon-enhanced hydrated salt PCM composites are briefly described. By introducing representative PCM composites loaded with carbon nanotubes, carbon fibers, graphene oxide, graphene, expanded graphite, biochar, activated carbon and multifunctional carbon, the ways that one-dimensional, two-dimensional, three-dimensional and hybrid carbon materials enhance the comprehensive thermophysical properties of hydrated salts and affect their phase change behavior is systematically discussed. Through analyzing the enhancement effects of different carbon fillers, the rationale for achieving the optimal performance of the PCM composites, including both thermal conductivity and phase change stability, is summarized. Regarding the applications of carbon-enhanced hydrate salt composites, their use for the thermal management of electronic devices, buildings and the human body is highlighted. Finally, research challenges for further improving the overall thermophysical properties of carbon-enhanced hydrated salt PCMs and pushing towards practical applications and potential research directions are discussed. It is expected that this timely review could provide valuable guidelines for the further development of carbon-enhanced hydrated salt composites and stimulate concerted research efforts from diverse communities to promote the widespread applications of high-performance PCM composites. Full article

(This article belongs to the Special Issue Advances in Nano-Enhanced Thermal Functional Materials)

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15 pages, 3802 KiB

Open AccessEditor’s ChoiceArticle

Magnetic Particle Imaging-Guided Thermal Simulations for Magnetic Particle Hyperthermia

by Hayden Carlton, Nageshwar Arepally, Sean Healy, Anirudh Sharma, Sarah Ptashnik, Maureen Schickel, Matt Newgren, Patrick Goodwill, Anilchandra Attaluri and Robert Ivkov

Nanomaterials 2024, 14(12), 1059; https://doi.org/10.3390/nano14121059 - 20 Jun 2024

Viewed by 976

Abstract

Magnetic particle hyperthermia (MPH) enables the direct heating of solid tumors with alternating magnetic fields (AMFs). One challenge with MPH is the unknown particle distribution in tissue after injection. Magnetic particle imaging (MPI) can measure the nanoparticle content and distribution in tissue after [...] Read more.

Magnetic particle hyperthermia (MPH) enables the direct heating of solid tumors with alternating magnetic fields (AMFs). One challenge with MPH is the unknown particle distribution in tissue after injection. Magnetic particle imaging (MPI) can measure the nanoparticle content and distribution in tissue after delivery. The objective of this study was to develop a clinically translatable protocol that incorporates MPI data into finite element calculations for simulating tissue temperatures during MPH. To verify the protocol, we conducted MPH experiments in tumor-bearing mouse cadavers. Five 8–10-week-old female BALB/c mice bearing subcutaneous 4T1 tumors were anesthetized and received intratumor injections of Synomag^®-S90 nanoparticles. Immediately following injection, the mice were euthanized and imaged, and the tumors were heated with an AMF. We used the Mimics Innovation Suite to create a 3D mesh of the tumor from micro-computerized tomography data and spatial index MPI to generate a scaled heating function for the heat transfer calculations. The processed imaging data were incorporated into a finite element solver, COMSOL Multiphysics^®. The upper and lower bounds of the simulated tumor temperatures for all five cadavers demonstrated agreement with the experimental temperature measurements, thus verifying the protocol. These results demonstrate the utility of MPI to guide predictive thermal calculations for MPH treatment planning. Full article

(This article belongs to the Special Issue Applications of Nanomaterials in Biomedical Imaging and Cancer Therapy II)

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18 pages, 3322 KiB

Open AccessEditor’s ChoiceArticle

Protocrystallinity of Monodispersed Ultra-Small Templated Mesoporous Silica Nanoparticles

by Laurent Bonneviot, Belén Albela, Feifei Gao, Pascal Perriat, Thierry Epicier and Mohamad El Eter

Nanomaterials 2024, 14(12), 1052; https://doi.org/10.3390/nano14121052 - 19 Jun 2024

Viewed by 558

Abstract

Monodisperse and semi-faceted ultra-small templated mesoporous silica nanoparticles (US-MSNs) of 20–25 nm were synthesized using short-time hydrolysis of tetraethoxysilane (TEOS) at room temperature, followed by a dilution for nucleation quenching. According to dynamic light scattering (DLS), a two-step pH adjustment was necessary for [...] Read more.

Monodisperse and semi-faceted ultra-small templated mesoporous silica nanoparticles (US-MSNs) of 20–25 nm were synthesized using short-time hydrolysis of tetraethoxysilane (TEOS) at room temperature, followed by a dilution for nucleation quenching. According to dynamic light scattering (DLS), a two-step pH adjustment was necessary for growth termination and colloidal stabilization. The pore size was controlled by cetyltrimethylammonium bromide (CTAB), and a tiny amount of neutral surfactant F127 was added to minimize the coalescence between US-MSNs and to favor the transition towards internal ordering. Flocculation eventually occurred, allowing us to harvest a powder by centrifugation (~60% silica yield after one month). Scanning transmission electron microscopy (STEM) and 3D high-resolution transmission electron microscopy (3D HR-TEM) images revealed that the US-MSNs are partially ordered. The 2D FT transform images provide evidence for the coexistence of four-, five-, and sixfold patterns characterizing an “on-the-edge” crystallization step between amorphous raspberry and hexagonal pore array morphologies, typical of a protocrystalline state. Calcination preserved this state and yielded a powder characterized by packing, developing a hierarchical porosity centered at 3.9 ± 0.2 (internal pores) and 68 ± 7 nm (packing voids) of high potential for support for separation and catalysis. Full article

(This article belongs to the Special Issue Advanced Porous Nanomaterials: Synthesis, Properties, and Application)

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31 pages, 16978 KiB

Open AccessEditor’s ChoiceArticle

Synthesis and Characterization of Composite WO₃ Fibers/g-C₃N₄ Photocatalysts for the Removal of the Insecticide Clothianidin in Aquatic Media

by Christos Lykos, Feidias Bairamis, Christina Efthymiou and Ioannis Konstantinou

Nanomaterials 2024, 14(12), 1045; https://doi.org/10.3390/nano14121045 - 18 Jun 2024

Viewed by 609

Abstract

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional [...] Read more.

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional photocatalysts (e.g., TiO₂, ZnO, etc.) that utilize only UV light for activation, the interest of the scientific community has recently focused on the development and application of visible light-activated photocatalysts like g-C₃N₄. However, some disadvantages of g-C₃N₄, such as the high recombination rate of photogenerated charges, limit its utility. In this light, the present study focuses on the synthesis of WO₃ fibers/g-C₃N₄ Z-scheme heterojunctions to improve the efficiency of g-C₃N₄ towards the photocatalytic removal of the widely used insecticide clothianidin. The effect of two different g-C₃N₄ precursors (urea and thiourea) and of WO₃ fiber content on the properties of the synthesized composite materials was also investigated. All aforementioned materials were characterized by a number of techniques (XRD, SEM-EDS, ATR-FTIR, Raman spectroscopy, DRS, etc.). According to the results, mixing 6.5% ^W/_W WO₃ fibers with either urea or thiourea derived g-C₃N₄ significantly increased the photocatalytic activity of the resulting composites compared to the precursor materials. In order to further elucidate the effect of the most efficient composite photocatalyst in the degradation of clothianidin, the generated transformation products were tentatively identified through UHPLC tandem high-resolution mass spectroscopy. Finally, the detoxification effect of the most efficient process was also assessed by combining the results of an in-vitro methodology and the predictions of two in-silico tools. Full article

(This article belongs to the Section Environmental Nanoscience and Nanotechnology)

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33 pages, 8395 KiB

Open AccessEditor’s ChoiceReview

Recent Progress on the Adsorption of Heavy Metal Ions Pb(II) and Cu(II) from Wastewater

by Dikang Fan, Yang Peng, Xi He, Jing Ouyang, Liangjie Fu and Huaming Yang

Nanomaterials 2024, 14(12), 1037; https://doi.org/10.3390/nano14121037 - 16 Jun 2024

Viewed by 687

Abstract

With the processes of industrialization and urbanization, heavy metal ion pollution has become a thorny problem in water systems. Among the various technologies developed for the removal of heavy metal ions, the adsorption method is widely studied by researchers and various nanomaterials with [...] Read more.

With the processes of industrialization and urbanization, heavy metal ion pollution has become a thorny problem in water systems. Among the various technologies developed for the removal of heavy metal ions, the adsorption method is widely studied by researchers and various nanomaterials with good adsorption performances have been prepared during the past decades. In this paper, a variety of novel nanomaterials with excellent adsorption performances for Pb(II) and Cu(II) reported in recent years are reviewed, such as carbon-based materials, clay mineral materials, zero-valent iron and their derivatives, MOFs, nanocomposites, etc. The novel nanomaterials with extremely high adsorption capacity, selectivity and particular nanostructures are summarized and introduced, along with their advantages and disadvantages. And, some future research priorities for the treatment of wastewater are also prospected. Full article

(This article belongs to the Special Issue The Applications of Nanomaterials for the Treatment of Heavy Metal-Polluted Water and Soils)

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12 pages, 3585 KiB

Open AccessEditor’s ChoiceArticle

High-Performance LiNbO₃ Domain Wall Memory Devices with Enhanced Selectivity via Optimized Metal–Semiconductor Contact

by Haiqing Jiang, Cuihua Dai, Bowen Shen and Jun Jiang

Nanomaterials 2024, 14(12), 1031; https://doi.org/10.3390/nano14121031 - 14 Jun 2024

Viewed by 618

Abstract

Lithium niobate (LiNbO₃) single-crystal nanodevices featuring elevated readout domain wall currents exhibit significant potential for integrated circuits in memory computing applications. Nevertheless, challenges stem from suboptimal electrode–LiNbO₃ single crystal contact characteristics, which impact the stability of high currents within these [...] Read more.

Lithium niobate (LiNbO₃) single-crystal nanodevices featuring elevated readout domain wall currents exhibit significant potential for integrated circuits in memory computing applications. Nevertheless, challenges stem from suboptimal electrode–LiNbO₃ single crystal contact characteristics, which impact the stability of high currents within these devices. In this work, we concentrate on augmenting the domain wall current by refining the fabrication processes of domain wall random access memory (DWRAM). Each LiNbO₃ domain wall nanodevice was fabricated using a self-aligned process. Device performance was significantly enhanced by introducing a 10 nm interlayer between the LiNbO₃ and Cu electrodes. A comparative analysis of electrical properties was conducted on devices with interlayers made of chromium (Cr) and titanium (Ti), as well as devices without interlayers. After the introduction of the Ti interlayer, the device’s coercive voltage demonstrated an 82% reduction, while the current density showed a remarkable 94-fold increase. A 100 nm sized device with the Ti interlayer underwent positive down–negative up pulse testing, demonstrating a writing time of 82 ns at 8 V and an erasing time of 12 μs at −9 V. These operating speeds are significantly faster than those of devices without interlayers. Moreover, the enhanced devices exhibited symmetrical domain switching hysteresis loops with retention times exceeding 10⁶ s. Notably, the coercive voltage (V_c) dispersion remained narrow after more than 1000 switching cycles. At an elevated temperature of 400 K, the device’s on/off ratio was maintained at 10⁵. The device’s embedded selector demonstrated an ultrahigh selectivity (>10⁶) across various reading voltages. These results underscore the viability of high-density nanoscale integration of ferroelectric domain wall memory. Full article

(This article belongs to the Special Issue Innovative Nanostructured Semiconductors for Electronic Devices)

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13 pages, 3277 KiB

Open AccessEditor’s ChoiceArticle

Highly Conductive and Long-Term Stable Phosphorene-Based Nanocomposite for Radio-Frequency Antenna Application

by Kibum Song, Seungho Ha and Keun-Young Shin

Nanomaterials 2024, 14(12), 1013; https://doi.org/10.3390/nano14121013 - 12 Jun 2024

Viewed by 412

Abstract

In this study, an omnidirectional and high-performance free-standing monopole patch radio-frequency antenna was fabricated using a urea-functionalized phosphorene/TiO₂/polypyrrole (UTP) nanocomposite. The UTP nanocomposite antenna was fabricated via ball milling of urea-functionalized phosphorene, chemical oxidative polymerization of the UTP nanocomposite, and mechanical [...] Read more.

In this study, an omnidirectional and high-performance free-standing monopole patch radio-frequency antenna was fabricated using a urea-functionalized phosphorene/TiO₂/polypyrrole (UTP) nanocomposite. The UTP nanocomposite antenna was fabricated via ball milling of urea-functionalized phosphorene, chemical oxidative polymerization of the UTP nanocomposite, and mechanical pelletizing of the composite. Based on experiments, the proposed UTP nanocomposite-based antenna exhibited long-term stability in terms of electrical conductivity. After 12 weeks, a slight change in surface resistance was observed. The proposed antenna exhibited high radiation efficiency (78.2%) and low return loss (−36.6 dB). The results of this study suggest the potential of UTP nanocomposite antennas for applications in 5G technology. Full article

(This article belongs to the Section Nanocomposite Materials)

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14 pages, 5077 KiB

Open AccessEditor’s ChoiceArticle

Accurate Evaluation of Electro-Thermal Performance in Silicon Nanosheet Field-Effect Transistors with Schemes for Controlling Parasitic Bottom Transistors

by Jinsu Jeong, Sanguk Lee and Rock-Hyun Baek

Nanomaterials 2024, 14(12), 1006; https://doi.org/10.3390/nano14121006 - 10 Jun 2024

Viewed by 472

Abstract

The electro-thermal performance of silicon nanosheet field-effect transistors (NSFETs) with various parasitic bottom transistor (tr_pbt)-controlling schemes is evaluated. Conventional punch-through stopper, trench inner-spacer (TIS), and bottom oxide (BOX) schemes were investigated from single-device to circuit-level evaluations to avoid overestimating heat’s [...] Read more.

The electro-thermal performance of silicon nanosheet field-effect transistors (NSFETs) with various parasitic bottom transistor (tr_pbt)-controlling schemes is evaluated. Conventional punch-through stopper, trench inner-spacer (TIS), and bottom oxide (BOX) schemes were investigated from single-device to circuit-level evaluations to avoid overestimating heat’s impact on performance. For single-device evaluations, the TIS scheme maintains the device temperature 59.6 and 50.4 K lower than the BOX scheme for n/pFETs, respectively, due to the low thermal conductivity of BOX. However, when the over-etched S/D recess depth (T_SD) exceeds 2 nm in the TIS scheme, the RC delay becomes larger than that of the BOX scheme due to increased gate capacitance (C_gg) as the T_SD increases. A higher TIS height prevents the C_gg increase and exhibits the best electro-thermal performance at single-device operation. Circuit-level evaluations are conducted with ring oscillators using 3D mixed-mode simulation. Although TIS and BOX schemes have similar oscillation frequencies, the TIS scheme has a slightly lower device temperature. This thermal superiority of the TIS scheme becomes more pronounced as the load capacitance (C_L) increases. As C_L increases from 1 to 10 fF, the temperature difference between TIS and BOX schemes widens from 1.5 to 4.8 K. Therefore, the TIS scheme is most suitable for controlling tr_pbt and improving electro-thermal performance in sub-3 nm node NSFETs. Full article

(This article belongs to the Special Issue Nanostructured Electronic Components and Devices)

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12 pages, 5214 KiB

Open AccessEditor’s ChoiceArticle

Electrocatalytic Oxidation of Benzaldehyde on Gold Nanoparticles Supported on Titanium Dioxide

by Li Gong, Yu Jin, Shiling Zhao, Kaizhi Wang, Paulina R. Martínez-Alanis and Andreu Cabot

Nanomaterials 2024, 14(12), 1005; https://doi.org/10.3390/nano14121005 - 10 Jun 2024

Viewed by 585

Abstract

The electrooxidation of organic compounds offers a promising strategy for producing value-added chemicals through environmentally sustainable processes. A key challenge in this field is the development of electrocatalysts that are both effective and durable. In this study, we grow gold nanoparticles (Au NPs) [...] Read more.

The electrooxidation of organic compounds offers a promising strategy for producing value-added chemicals through environmentally sustainable processes. A key challenge in this field is the development of electrocatalysts that are both effective and durable. In this study, we grow gold nanoparticles (Au NPs) on the surface of various phases of titanium dioxide (TiO₂) as highly effective electrooxidation catalysts. Subsequently, the samples are tested for the oxidation of benzaldehyde (BZH) to benzoic acid (BZA) coupled with a hydrogen evolution reaction (HER). We observe the support containing a combination of rutile and anatase phases to provide the highest activity. The excellent electrooxidation performance of this Au-TiO₂ sample is correlated with its mixed-phase composition, large surface area, high oxygen vacancy content, and the presence of Lewis acid active sites on its surface. This catalyst demonstrates an overpotential of 0.467 V at 10 mA cm⁻² in a 1 M KOH solution containing 20 mM BZH, and 0.387 V in 100 mM BZH, well below the oxygen evolution reaction (OER) overpotential. The electrooxidation of BZH not only serves as OER alternative in applications such as electrochemical hydrogen evolution, enhancing energy efficiency, but simultaneously allows for the generation of high-value byproducts such as BZA. Full article

(This article belongs to the Special Issue Advanced Nanostructures for Electrochemical Energy Conversion and Storage)

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11 pages, 3998 KiB

Open AccessEditor’s ChoiceArticle

Flexible Mechanical Sensors Fabricated with Graphene Oxide-Coated Commercial Silk

by Hyun-Seok Jang, Ki Hoon Lee and Byung Hoon Kim

Nanomaterials 2024, 14(12), 1000; https://doi.org/10.3390/nano14121000 - 8 Jun 2024

Viewed by 679

Abstract

Many studies on flexible strain and pressure sensors have been reported due to growing interest in wearable devices for healthcare purposes. Here, we present flexible pressure and strain (motion) sensors prepared with only graphene oxide (GO) and commercial silk fabrics and yarns. The [...] Read more.

Many studies on flexible strain and pressure sensors have been reported due to growing interest in wearable devices for healthcare purposes. Here, we present flexible pressure and strain (motion) sensors prepared with only graphene oxide (GO) and commercial silk fabrics and yarns. The pressure sensors were fabricated by simply dipping the silk fabric into GO solution followed by applying a thermal treatment at 400 °C to obtain reduced GO (rGO). The pressure sensors were made from rGO-coated fabrics, which were stacked in three, five, and seven layers. A super-sensitivity of 2.58 × 10³ kPa⁻¹ at low pressure was observed in the seven-layer pressure sensor. The strain sensors were obtained from rGO-coated twisted silk yarns whose gauge factor was 0.307. Although this value is small or comparable to the values for other sensors, it is appropriate for motion sensing. The results of this study show a cost-effective and simple method for the fabrication of pressure and motion sensors with commercial silk and GO. Full article

(This article belongs to the Special Issue Carbon Nanostructures as Promising Future Materials: 2nd Edition)

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10 pages, 3667 KiB

Open AccessEditor’s ChoiceArticle

Chemical Bath Deposition of ZnO/ZnGa₂O₄ Core–Shell Nanowire Heterostructures Using Partial Chemical Conversion

by Guislain Hector, Estelle Appert, Hervé Roussel, Anna Bujak, Eirini Sarigiannidou and Vincent Consonni

Nanomaterials 2024, 14(12), 991; https://doi.org/10.3390/nano14120991 - 7 Jun 2024

Viewed by 631

Abstract

The development of innovative heterostructures made of ZnO nanowires is of great interest for enhancing the performances of many devices in the fields of optoelectronics, photovoltaics, and energy harvesting. We report an original fabrication process to form ZnO/ZnGa₂O₄ core–shell nanowire [...] Read more.

The development of innovative heterostructures made of ZnO nanowires is of great interest for enhancing the performances of many devices in the fields of optoelectronics, photovoltaics, and energy harvesting. We report an original fabrication process to form ZnO/ZnGa₂O₄ core–shell nanowire heterostructures in the framework of the wet chemistry techniques. The process involves the partial chemical conversion of ZnO nanowires grown via chemical bath deposition into ZnO/ZnGa₂O₄ core–shell nanowire heterostructures with a high interface quality following their immersion in an aqueous solution containing gallium nitrate heated at a low temperature. The double-step process describing the partial chemical conversion relies on successive dissolution and reaction mechanisms. The present finding offers the possibility to fabricate ZnO/ZnGa₂O₄ core–shell nanowire heterostructures at low temperatures and over a wide variety of substrates with a large surface area, which is attractive for nanostructured solar cells, deep-UV photodetectors, and piezoelectric devices. Full article

(This article belongs to the Section Nanofabrication and Nanomanufacturing)

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18 pages, 2250 KiB

Open AccessEditor’s ChoiceReview

Emerging Trends in Nanotechnology for Endometriosis: Diagnosis to Therapy

by Souvanik Talukdar, Santosh K. Singh, Manoj K. Mishra and Rajesh Singh

Nanomaterials 2024, 14(11), 976; https://doi.org/10.3390/nano14110976 - 5 Jun 2024

Viewed by 958

Abstract

Endometriosis, an incurable gynecological disease that causes abnormal growth of uterine-like tissue outside the uterine cavity, leads to pelvic pain and infertility in millions of individuals. Endometriosis can be treated with medicine and surgery, but recurrence and comorbidities impair quality of life. In [...] Read more.

Endometriosis, an incurable gynecological disease that causes abnormal growth of uterine-like tissue outside the uterine cavity, leads to pelvic pain and infertility in millions of individuals. Endometriosis can be treated with medicine and surgery, but recurrence and comorbidities impair quality of life. In recent years, nanoparticle (NP)-based therapy has drawn global attention, notably in medicine. Studies have shown that NPs could revolutionize conventional therapeutics and imaging. Researchers aim to enhance the prognosis of endometriosis patients with less invasive and more effective NP-based treatments. This study evaluates this potential paradigm shift in endometriosis management, exploring NP-based systems for improved treatments and diagnostics. Insights into nanotechnology applications, including gene therapy, photothermal therapy, immunotherapy, and magnetic hyperthermia, offering a theoretical reference for the clinical use of nanotechnology in endometriosis treatment, are discussed in this review. Full article

(This article belongs to the Special Issue Advanced Nanomaterials in Biomedical Application (2nd Edition))

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11 pages, 3653 KiB

Open AccessEditor’s ChoiceArticle

Defects in Nitrogen-Doped ZnO Nanoparticles and Their Effect on Light-Emitting Diodes

by Raj Deep, Toshiyuki Yoshida and Yasuhisa Fujita

Nanomaterials 2024, 14(11), 977; https://doi.org/10.3390/nano14110977 - 5 Jun 2024

Cited by 1 | Viewed by 1016

Abstract

In this study, the effect of defects on the acceptor properties of nitrogen-doped ZnO nanoparticles (NPs) was investigated through the fabrication of light-emitting diodes (LEDs). Nitrogen-doped ZnO NPs were synthesized by an arc discharge in-gas evaporation method and post-annealed at 800 °C in [...] Read more.

In this study, the effect of defects on the acceptor properties of nitrogen-doped ZnO nanoparticles (NPs) was investigated through the fabrication of light-emitting diodes (LEDs). Nitrogen-doped ZnO NPs were synthesized by an arc discharge in-gas evaporation method and post-annealed at 800 °C in an oxygen and nitrogen atmosphere. The annealed ZnO NPs were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. It was found that the annealing of nitrogen-doped ZnO NPs in a nitrogen environment increased the number of zinc vacancies, while annealing in an oxygen environment increased the number of oxygen vacancies due to nitrogen desorption. The output characteristics of LEDs fabricated with oxygen-annealed NPs were degraded, while those with nitrogen-annealed NPs were significantly improved. From these results, the contribution of zinc vacancies to acceptor formation in ZnO NPs was confirmed for the first time in actual pn junction devices. Full article

(This article belongs to the Special Issue Synthesis, Characterization, and Application of Luminescent Nanomaterials)

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18 pages, 2939 KiB

Open AccessEditor’s ChoiceArticle

Structural, Electrical, and Optical Properties of Single-Walled Carbon Nanotubes Synthesized through Floating Catalyst Chemical Vapor Deposition

by Melorina Dolafi Rezaee, Biplav Dahal, John Watt, Mahir Abrar, Deidra R. Hodges and Wenzhi Li

Nanomaterials 2024, 14(11), 965; https://doi.org/10.3390/nano14110965 - 2 Jun 2024

Viewed by 918

Abstract

Single-walled carbon nanotube (SWCNT) thin films were synthesized by using a floating catalyst chemical vapor deposition (FCCVD) method with a low flow rate (200 sccm) of mixed gases (Ar and H₂). SWCNT thin films with different thicknesses can be prepared by [...] Read more.

Single-walled carbon nanotube (SWCNT) thin films were synthesized by using a floating catalyst chemical vapor deposition (FCCVD) method with a low flow rate (200 sccm) of mixed gases (Ar and H₂). SWCNT thin films with different thicknesses can be prepared by controlling the collection time of the SWCNTs on membrane filters. Transmission electron microscopy (TEM) showed that the SWCNTs formed bundles and that they had an average diameter of 1.46 nm. The Raman spectra of the SWCNT films suggested that the synthesized SWCNTs were very well crystallized. Although the electrical properties of SWCNTs have been widely studied so far, the Hall effect of SWCNTs has not been fully studied to explore the electrical characteristics of SWCNT thin films. In this research, Hall effect measurements have been performed to investigate the important electrical characteristics of SWCNTs, such as their carrier mobility, carrier density, Hall coefficient, conductivity, and sheet resistance. The samples with transmittance between 95 and 43% showed a high carrier density of 10²¹–10²³ cm⁻³. The SWCNTs were also treated using Brønsted acids (HCl, HNO₃, H₂SO₄) to enhance their electrical properties. After the acid treatments, the samples maintained their p-type nature. The carrier mobility and conductivity increased, and the sheet resistance decreased for all treated samples. The highest mobility of 1.5 cm²/Vs was obtained with the sulfuric acid treatment at 80 °C, while the highest conductivity (30,720 S/m) and lowest sheet resistance (43 ohm/square) were achieved with the nitric acid treatment at room temperature. Different functional groups were identified in our synthesized SWCNTs before and after the acid treatments using Fourier-Transform Infrared Spectroscopy (FTIR). Full article

(This article belongs to the Special Issue Advances in Carbon Nanotubes: Synthesis, Properties, and Cutting-Edge Applications)

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15 pages, 3500 KiB

Open AccessEditor’s ChoiceArticle

Magnet-Guided Temozolomide and Ferucarbotran Loaded Nanoparticles to Enhance Therapeutic Efficacy in Glioma Model

by Reju George Thomas, Subin Kim, Thi-Anh-Thuy Tran, Young Hee Kim, Raveena Nagareddy, Tae-Young Jung, Seul Kee Kim and Yong Yeon Jeong

Nanomaterials 2024, 14(11), 939; https://doi.org/10.3390/nano14110939 - 27 May 2024

Viewed by 563

Abstract

Background. The aim of the study was to synthesize liposomal nanoparticles loaded with temozolomide and ferucarbotran (LTF) and to evaluate the theranostic effect of LTF in the glioma model. Methods. We synthesized an LTF that could pass through the Blood Brain Barrier (BBB) [...] Read more.

Background. The aim of the study was to synthesize liposomal nanoparticles loaded with temozolomide and ferucarbotran (LTF) and to evaluate the theranostic effect of LTF in the glioma model. Methods. We synthesized an LTF that could pass through the Blood Brain Barrier (BBB) and localize in brain tumor tissue with the help of magnet guidance. We examined the chemical characteristics. Cellular uptake and cytotoxicity studies were conducted in vitro. A biodistribution and tumor inhibition study was conduted using an in vivo glioma model. Results. The particle size and surface charge of LTF show 108 nm and −38 mV, respectively. Additionally, the presence of ferucarbotran significantly increased the contrast agent effect of glioma compared to the control group in MR imaging. Magnet-guided LTF significantly reduced the tumor size compared to control and other groups. Furthermore, compared to the control group, our results demonstrate a significant inhibition in brain tumor size and an increase in lifespan. Conclusions. These findings suggest that the LTF with magnetic guidance represents a novel approach to address current obstacles, such as BBB penetration of nanoparticles and drug resistance. Magnet-guided LTF is able to enhance therapeutic efficacy in mouse brain glioma. Full article

(This article belongs to the Special Issue Applications of Nanomaterials in Biomedical Imaging and Cancer Therapy II)

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13 pages, 3513 KiB

Open AccessEditor’s ChoiceArticle

Amorphous Fe₂O₃ Anchored on N-Doped Graphene with Internal Micro-Channels as an Active and Durable Anode for Sodium-Ion Batteries

by Lin Li, Hui Li, Linxin Liu, Xunchang Yan, Yunze Long and Wenpeng Han

Nanomaterials 2024, 14(11), 937; https://doi.org/10.3390/nano14110937 - 27 May 2024

Viewed by 588

Abstract

The reduced graphene oxide (rGO) exhibits outstanding electrical conductivity and a high specific surface area, making it a promising material for various applications. Fe₂O₃ is highly desirable due to its significant theoretical capacity and cost-effectiveness, high abundance, and environmental friendliness. [...] Read more.

The reduced graphene oxide (rGO) exhibits outstanding electrical conductivity and a high specific surface area, making it a promising material for various applications. Fe₂O₃ is highly desirable due to its significant theoretical capacity and cost-effectiveness, high abundance, and environmental friendliness. However, the performance of these r-GO/Fe₂O₃ composite electrodes still needs to be further improved, especially in terms of cycle stability. The composite of Fe₂O₃ anchored on N-doped graphene with inside micro-channels (Fe₂O₃@N-GIMC) was used to be efficiently prepared. Because the inside channels can furnish extra transmission pathways and absorption websites and the interconnected structure can efficaciously forestall pulverization and aggregation of electrode materials. In addition, N doping is also beneficial to improve its electrochemical performance. Thus, it demonstrates exceptional sodium storage characteristics, including notable electrochemical activity, impressive initial Coulombic efficiency, and favorable rate performance. The optimized Fe₂O₃@N-GIMC indicates outstanding discharge capacity (573.5 mAh g⁻¹ at 1 A g⁻¹), significant rate performance (333.6 mAh g⁻¹ at 8 A g⁻¹), and stable long-term cycle durability (308.9 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹, 200.8 mAh g⁻¹ after 4000 cycles at 1 A g⁻¹) as a sodium-ion battery anode. This presents a new approach for preparing graphene-based high-functional composites and lays a stable basis for further expanding its application field. Full article

(This article belongs to the Special Issue Synthesis & Devices of Graphene-Based 2D Nanomaterials for Energy Storage and Conversion)

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25 pages, 6668 KiB

Open AccessEditor’s ChoiceArticle

Two-Dimensional MoS₂ Nanosheets Derived from Cathodic Exfoliation for Lithium Storage Applications

by Alberto Martínez-Jódar, Silvia Villar-Rodil, José M. Munuera, Alberto Castro-Muñiz, Jonathan N. Coleman, Encarnación Raymundo-Piñero and Juan I. Paredes

Nanomaterials 2024, 14(11), 932; https://doi.org/10.3390/nano14110932 - 25 May 2024

Viewed by 574

Abstract

The preparation of 2H-phase MoS₂ thin nanosheets by electrochemical delamination remains a challenge, despite numerous efforts in this direction. In this work, by choosing appropriate intercalating cations for cathodic delamination, the insertion process was facilitated, leading to a higher degree of exfoliation [...] Read more.

The preparation of 2H-phase MoS₂ thin nanosheets by electrochemical delamination remains a challenge, despite numerous efforts in this direction. In this work, by choosing appropriate intercalating cations for cathodic delamination, the insertion process was facilitated, leading to a higher degree of exfoliation while maintaining the original 2H-phase of the starting bulk MoS₂ material. Specifically, trimethylalkylammonium cations were tested as electrolytes, outperforming their bulkier tetraalkylammonium counterparts, which have been the focus of past studies. The performance of novel electrochemically derived 2H-phase MoS₂ nanosheets as electrode material for electrochemical energy storage in lithium-ion batteries was investigated. The lower thickness and thus higher flexibility of cathodically exfoliated MoS₂ promoted better electrochemical performance compared to liquid-phase and ultrasonically assisted exfoliated MoS₂, both in terms of capacity (447 vs. 371 mA·h·g⁻¹ at 0.2 A·g⁻¹) and rate capability (30% vs. 8% capacity retained when the current density was increased from 0.2 A·g⁻¹ to 5 A·g⁻¹), as well as cycle life (44% vs. 17% capacity retention at 0.2 A·g⁻¹ after 580 cycles). Overall, the present work provides a convenient route for obtaining MoS₂ thin nanosheets for their advantageous use as anode material for lithium storage. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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18 pages, 7036 KiB

Open AccessEditor’s ChoiceArticle

Magnetic Iron Oxide Nanoparticles Coated by Coumarin-Bound Copolymer for Enhanced Magneto- and Photothermal Heating and Luminescent Thermometry

by Alexiane Féron, Sylvain Catrouillet, Saad Sene, Gautier Félix, Belkacem Tarek Benkhaled, Vincent Lapinte, Yannick Guari and Joulia Larionova

Nanomaterials 2024, 14(11), 906; https://doi.org/10.3390/nano14110906 - 22 May 2024

Viewed by 820

Abstract

In this work, we report on the synthesis and investigation of new hybrid multifunctional iron oxide nanoparticles (IONPs) coated by coumarin-bound copolymer, which combine magneto- or photothermal heating with luminescent thermometry. A series of amphiphilic block copolymers, including Coum-C₁₁-PPhOx₂₇-PMOx [...] Read more.

In this work, we report on the synthesis and investigation of new hybrid multifunctional iron oxide nanoparticles (IONPs) coated by coumarin-bound copolymer, which combine magneto- or photothermal heating with luminescent thermometry. A series of amphiphilic block copolymers, including Coum-C₁₁-PPhOx₂₇-PMOx₅₉ and Coum-C₁₁-PButOx₈-PMOx₄₂ bearing luminescent and photodimerizable coumarin moiety, as well as coumarin-free PPhOx₂₇-PMOx₅₇, were evaluated for their utility as luminescent thermometers and for encapsulating spherical 26 nm IONPs. The obtained IONP@Coum-C₁₁-PPhOx₂₇-PMOx₅₉ nano-objects are perfectly dispersible in water and able to provide macroscopic heating remotely triggered by an alternating current magnetic field (AMF) with a specific absorption rate (SAR) value of 240 W.g⁻¹ or laser irradiation with a photothermal conversion efficiency of η = 68%. On the other hand, they exhibit temperature-dependent emission of coumarin offering the function of luminescent thermometer, which operates in the visible region between 20 °C and 60 °C in water displaying a maximal relative thermal sensitivity (S_r) of 1.53%·°C⁻¹ at 60 °C. Full article

(This article belongs to the Special Issue Luminescent Nanomaterials: Functional Design, Advantages, and Applications)

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17 pages, 3508 KiB

Open AccessEditor’s ChoiceArticle

Targeting Inflammation and Oxidative Stress to Improve Outcomes in a TNBS Murine Crohn’s Colitis Model

by Anisha Apte, James R. Bardill, Jimena Canchis, Stacy M. Skopp, Tobias Fauser, Bailey Lyttle, Alyssa E. Vaughn, Sudipta Seal, David M. Jackson, Kenneth W. Liechty and Carlos Zgheib

Nanomaterials 2024, 14(10), 894; https://doi.org/10.3390/nano14100894 - 20 May 2024

Viewed by 772

Abstract

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn’s disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a [...] Read more.

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn’s disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) mouse model for Crohn’s disease by decreasing colonic inflammation. Balb/c mice were instilled with TNBS enemas to induce colitis. Two days later, the mice received cellulose gel enema, cellulose gel with CNP-miR146a enema, or no treatment. Control mice received initial enemas of 50% ethanol and PBS enemas on day two. The mice were monitored daily for weight loss and clinical disease activity. The mice were euthanized on days two or five to evaluate their miR146a expression, inflammation on histology, and colonic IL-6 and TNF gene expressions and protein concentrations. CNP-miR146a enema successfully increased colonic miR146a expression at 12 h following delivery. At the end of five days from TNBS instillation, the mice treated with CNP-miR146a demonstrated reduced weight loss, improved inflammation scores on histology, and reduced gene expressions and protein concentrations of IL-6 and TNF. The local delivery of CNP-miR146a in a TNBS mouse model of acute Crohn’s colitis dramatically decreased inflammatory signaling, resulting in improved clinical disease. Full article

(This article belongs to the Section Biology and Medicines)

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20 pages, 18539 KiB

Open AccessEditor’s ChoiceReview

Nanostructured Flame-Retardant Layer-by-Layer Architectures for Cotton Fabrics: The Current State of the Art and Perspectives

by Giulio Malucelli

Nanomaterials 2024, 14(10), 858; https://doi.org/10.3390/nano14100858 - 15 May 2024

Viewed by 937

Abstract

Nowadays, nanotechnology represents a well-established approach, suitable for designing, producing, and applying materials to a broad range of advanced sectors. In this context, the use of well-suited “nano” approaches accounted for a big step forward in conferring optimized flame-retardant features to such a [...] Read more.

Nowadays, nanotechnology represents a well-established approach, suitable for designing, producing, and applying materials to a broad range of advanced sectors. In this context, the use of well-suited “nano” approaches accounted for a big step forward in conferring optimized flame-retardant features to such a cellulosic textile material as cotton, considering its high ease of flammability, yearly production, and extended use. Being a surface-localized phenomenon, the flammability of cotton can be quite simply and effectively controlled by tailoring its surface through the deposition of nano-objects, capable of slowing down the heat and mass transfer from and to the textile surroundings, which accounts for flame fueling and possibly interacting with the propagating radicals in the gas phase. In this context, the layer-by-layer (LbL) approach has definitively demonstrated its reliability and effectiveness in providing cotton with enhanced flame-retardant features, through the formation of fully inorganic or hybrid organic/inorganic nanostructured assemblies on the fabric surface. Therefore, the present work aims to summarize the current state of the art related to the use of nanostructured LbL architectures for cotton flame retardancy, offering an overview of the latest research outcomes that often highlight the multifunctional character of the deposited assemblies and discussing the current limitations and some perspectives. Full article

(This article belongs to the Special Issue Nanomaterials and Textiles)

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17 pages, 26158 KiB

Open AccessEditor’s ChoiceArticle

Synthesis of Controllable Superparamagnetic Nano Fe₃O₄ Based on Reduction Method for Colloidal Clusters of Magnetically Responsive Photonic Crystals

by Jun Chen, Mengdong Tu, Mengying Xu, Depeng Gong, Xi Li and Chaocan Zhang

Nanomaterials 2024, 14(10), 852; https://doi.org/10.3390/nano14100852 - 14 May 2024

Viewed by 807

Abstract

In this paper, we designed and investigated a reduction-based method to synthesize controllably monodisperse superparamagnetic nano Fe₃O₄ colloidal clusters for magnetically responsive photonic crystals. It was shown that the addition of ascorbic acid (VC) to the system could synthesize monodisperse [...] Read more.

In this paper, we designed and investigated a reduction-based method to synthesize controllably monodisperse superparamagnetic nano Fe₃O₄ colloidal clusters for magnetically responsive photonic crystals. It was shown that the addition of ascorbic acid (VC) to the system could synthesize monodisperse superparamagnetic nano Fe₃O₄ and avoided the generation of γ-Fe₂O₃ impurities, while the particle size and saturation magnetization intensity of nano Fe₃O₄ gradually decreased with the increase of VC dosage. Nano Fe₃O₄ could be rapidly assembled into photonic crystal dot matrix structures under a magnetic field, demonstrating tunability to various diffraction wavelengths. The nano Fe₃O₄ modified by polyvinylpyrrolidone (PVP) and silicon coated could be stably dispersed in a variety of organic solvents and thus diffracted different wavelengths under a magnetic field. This is expected to be applied in various scenarios in the field of optical color development. Full article

(This article belongs to the Collection Magnetic Nanostructured Materials: Synthesis, Characterization and Their Cutting-Edge Applications)

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9 pages, 3703 KiB

Open AccessEditor’s ChoiceArticle

Chromatographic Assessment of Organic Compounds Using Carbon Nanotubes: The Relationship between Affinity and Dispersibility

by Taiyo Shimizu, Ryoichi Kishi, Atsushi Hirano, Ken Kokubo and Kenji Hata

Nanomaterials 2024, 14(10), 824; https://doi.org/10.3390/nano14100824 - 8 May 2024

Viewed by 814

Abstract

The affinity between carbon nanotubes (CNTs) and organic compounds is of substantial importance since it strongly relates to the dispersibility of CNTs in those compounds. Several affinity evaluation methods have been developed so far, and the concept of the Hansen solubility parameter is [...] Read more.

The affinity between carbon nanotubes (CNTs) and organic compounds is of substantial importance since it strongly relates to the dispersibility of CNTs in those compounds. Several affinity evaluation methods have been developed so far, and the concept of the Hansen solubility parameter is a representative method widely used in the field of nanocarbon materials. Here, we demonstrate that CNT-loaded silica columns can effectively assess the affinity of organic compounds for CNT surface by exploiting the chromatographic retention time as a criterion. Obtained trends of the affinity of organic compounds for CNT were compared to those based on Hansen solubility parameter distance values. Most organic compounds showed similar trends, but one exceptional compound was observed. Simple CNT dispersion tests were conducted with these organic compounds to demonstrate the advantage of the chromatographic assessment. Further, we conducted comparison experiments using a pyrene-functionalized column and other CNT-loaded columns to elucidate the characteristics of each CNT column. The chromatographic approaches using CNT columns would be beneficial for realizing CNT suspensions with improved CNT dispersibility. Full article

(This article belongs to the Special Issue Advances in Carbon Nanotubes: Synthesis, Properties, and Cutting-Edge Applications)

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28 pages, 9824 KiB

Open AccessEditor’s ChoiceReview

Magnetic Material in Triboelectric Nanogenerators: A Review

by Enqi Sun, Qiliang Zhu, Hafeez Ur Rehman, Tong Wu, Xia Cao and Ning Wang

Nanomaterials 2024, 14(10), 826; https://doi.org/10.3390/nano14100826 - 8 May 2024

Cited by 1 | Viewed by 1541

Abstract

Nowadays, magnetic materials are also drawing considerable attention in the development of innovative energy converters such as triboelectric nanogenerators (TENGs), where the introduction of magnetic materials at the triboelectric interface not only significantly enhances the energy harvesting efficiency but also promotes TENG entry [...] Read more.

Nowadays, magnetic materials are also drawing considerable attention in the development of innovative energy converters such as triboelectric nanogenerators (TENGs), where the introduction of magnetic materials at the triboelectric interface not only significantly enhances the energy harvesting efficiency but also promotes TENG entry into the era of intelligence and multifunction. In this review, we begin from the basic operating principle of TENGs and then summarize the recent progress in applications of magnetic materials in the design of TENG magnetic materials by categorizing them into soft ferrites and amorphous and nanocrystalline alloys. While highlighting key role of magnetic materials in and future opportunities for improving their performance in energy conversion, we also discuss the most promising choices available today and describe emerging approaches to create even better magnetic TENGs and TENG-based sensors as far as intelligence and multifunctionality are concerned. In addition, the paper also discusses the integration of magnetic TENGs as a power source for third-party sensors and briefly explains the self-powered applications in a wide range of related fields. Finally, the paper discusses the challenges and prospects of magnetic TENGs. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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18 pages, 5879 KiB

Open AccessEditor’s ChoiceArticle

Study on Microstructure and Tribological Mechanism of Mo Incorporated (AlCrTiZr)N High-Entropy Ceramics Coatings Prepared by Magnetron Sputtering

by Jia Zheng, Yiman Zhao, Jingchuan Li, Sam Zhang, Jian Zhang and Deen Sun

Nanomaterials 2024, 14(10), 814; https://doi.org/10.3390/nano14100814 - 7 May 2024

Viewed by 752

Abstract

(AlCrTiZrMo_x)N coatings with varying Mo content were successfully prepared using a multi-target co-deposition magnetron sputtering system. The results reveal that the Mo content significantly affects the microstructure, hardness, fracture toughness, and tribological behavior of the coatings. As the Mo content in [...] Read more.

(AlCrTiZrMo_x)N coatings with varying Mo content were successfully prepared using a multi-target co-deposition magnetron sputtering system. The results reveal that the Mo content significantly affects the microstructure, hardness, fracture toughness, and tribological behavior of the coatings. As the Mo content in the coatings increases gradually, the preferred orientation changes from (200) to (111). The coatings consistently exhibit a distinct columnar structure. Additionally, the hardness of the coatings increases from 24.39 to 30.24 GPa, along with an increase in fracture toughness. The friction coefficient is reduced from 0.72 to 0.26, and the wear rate is reduced by 10 times. During the friction process, the inter-column regions of the coatings are initially damaged, causing the wear track to exhibit a wavy pattern. Greater frictional heat is generated at the crest of the wave, resulting in the formation of a MoO₂ lubricating layer. The friction reaction helps to reduce the shear force during friction, demonstrating the lower friction coefficient of the (AlCrTiZrMo_x)N coatings. Both the hardness and fracture toughness work together to reduce the wear rate, and the (AlCrTiZrMo_x)N coatings show excellent wear resistance. Most notably, although the columnar structure plays a negative role in the hardness, it contributes greatly to the wear resistance. Full article

(This article belongs to the Special Issue Thin-Film Processing and Deposition Techniques)

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16 pages, 9116 KiB

Open AccessEditor’s ChoiceArticle

Interfacing Langmuir–Blodgett and Pickering Emulsions for the Synthesis of 2D Nanostructured Films: Applications in Copper Ion Adsorption

by Andrei Honciuc, Oana-Iuliana Negru and Mirela Honciuc

Nanomaterials 2024, 14(9), 809; https://doi.org/10.3390/nano14090809 - 6 May 2024

Viewed by 853

Abstract

This research focuses on developing a 2D thin film comprising a monolayer of silica nanoparticles functionalized with polyethyleneimine (PEI), achieved through a novel integration of Langmuir–Blodgett (L-B) and Pickering emulsion techniques. The primary aim was to create a nanostructured film that exhibits dual [...] Read more.

This research focuses on developing a 2D thin film comprising a monolayer of silica nanoparticles functionalized with polyethyleneimine (PEI), achieved through a novel integration of Langmuir–Blodgett (L-B) and Pickering emulsion techniques. The primary aim was to create a nanostructured film that exhibits dual functionality: iridescence and efficient metal ion adsorption, specifically Cu(II) ions. The methodology combined L-B and Pickering emulsion polymerization to assemble and stabilize a nanoparticle monolayer at an oil/water interface, which was then polymerized under UV radiation to form an asymmetrically structured film. The results demonstrate that the film possesses a high adsorption efficiency for Cu(II) ions, with the enhanced mechanical durability provided by a reinforcing layer of polyvinyl alcohol/glycerol. The advantage of combining L-B and Pickering emulsion technology is the ability to generate 2D films from functional nanoparticle monolayers that are sufficiently sturdy to be deployed in applications. The 2D film’s practical applications in environmental remediation were confirmed through its ability to adsorb and recover Cu(II) ions from aqueous solutions effectively. We thus demonstrate the film’s potential as a versatile tool in water treatment applications owing to its combined photonic and adsorptive properties. This work paves the way for future research on the use of nanoengineered films in environmental and possibly photonic applications focusing on enhancing the film’s structural robustness and exploring its broader applicability to other pollutants and metal ions. Full article

(This article belongs to the Special Issue Morphological Design and Synthesis of Nanoparticles (Second Edition))

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15 pages, 8158 KiB

Open AccessEditor’s ChoiceArticle

Repeated Injection of Very Small Superparamagnetic Iron Oxide Particles (VSOPs) in Murine Atherosclerosis: A Safety Study

by Tobias Haase, Antje Ludwig, Anke Stach, Azadeh Mohtashamdolatshahi, Ralf Hauptmann, Lars Mundhenk, Harald Kratz, Susanne Metzkow, Avan Kader, Christian Freise, Susanne Mueller, Nicola Stolzenburg, Patricia Radon, Maik Liebl, Frank Wiekhorst, Bernd Hamm, Matthias Taupitz and Jörg Schnorr

Nanomaterials 2024, 14(9), 773; https://doi.org/10.3390/nano14090773 - 28 Apr 2024

Viewed by 1042

Abstract

Citrate-coated electrostatically stabilized very small superparamagnetic iron oxide particles (VSOPs) have been successfully tested as magnetic resonance angiography (MRA) contrast agents and are promising tools for molecular imaging of atherosclerosis. Their repeated use in the background of pre-existing hyperlipidemia and atherosclerosis has not [...] Read more.

Citrate-coated electrostatically stabilized very small superparamagnetic iron oxide particles (VSOPs) have been successfully tested as magnetic resonance angiography (MRA) contrast agents and are promising tools for molecular imaging of atherosclerosis. Their repeated use in the background of pre-existing hyperlipidemia and atherosclerosis has not yet been studied. This study aimed to investigate the effect of multiple intravenous injections of VSOPs in atherosclerotic mice. Taurine-formulated VSOPs (VSOP-T) were repeatedly intravenously injected at 100 µmol Fe/kg in apolipoprotein E-deficient (ApoE KO) mice with diet-induced atherosclerosis. Angiographic imaging was carried out by in vivo MRI. Magnetic particle spectrometry was used to detect tissue VSOP content, and tissue iron content was quantified photometrically. Pathological changes in organs, atherosclerotic plaque development, and expression of hepatic iron-related proteins were evaluated. VSOP-T enabled the angiographic imaging of heart and blood vessels with a blood half-life of one hour. Repeated intravenous injection led to VSOP deposition and iron accumulation in the liver and spleen without affecting liver and spleen pathology, expression of hepatic iron metabolism proteins, serum lipids, or atherosclerotic lesion formation. Repeated injections of VSOP-T doses sufficient for MRA analyses had no significant effects on plaque burden, steatohepatitis, and iron homeostasis in atherosclerotic mice. These findings underscore the safety of VSOP-T and support its further development as a contrast agent and molecular imaging tool. Full article

(This article belongs to the Special Issue Advances in Nanotoxicology: Health and Safety)

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18 pages, 3872 KiB

Open AccessEditor’s ChoiceArticle

Biopolymer Meets Nanoclay: Rational Fabrication of Superb Adsorption Beads from Green Precursors for Efficient Capture of Pb(II) and Dyes

by Jie Qi, Xue Wang, Huan Zhang, Xiangyu Liu, Wenbo Wang, Qingdong He and Fang Guo

Nanomaterials 2024, 14(9), 766; https://doi.org/10.3390/nano14090766 - 26 Apr 2024

Viewed by 884

Abstract

Renewable, green, and safe natural biopolymer-derived materials are highly desired for the purification of pollutants, but significantly improving their performance without the introduction of additional harmful chemicals remains a huge challenge. Based on the concept of “structure optimization design”, environment-friendly composite beads (named [...] Read more.

Renewable, green, and safe natural biopolymer-derived materials are highly desired for the purification of pollutants, but significantly improving their performance without the introduction of additional harmful chemicals remains a huge challenge. Based on the concept of “structure optimization design”, environment-friendly composite beads (named SA/PASP/RE) with excellent adsorption performance and recyclability were rationally constructed through a green ionic crosslinking route, using the completely green biopolymer sodium alginate (SA), sodium salt of polyaspartic acid (PASP), and the natural nanoclay rectorite (RE) as starting materials. The nano-layered RE was embedded in the polymer matrix to prevent the polymer chain from becoming over-entangled so that more adsorption sites inside the polymer network were exposed, which effectively improved the mass transfer efficiency of the adsorbent and the removal rate of contaminants. The composite beads embedded with 0.6% RE showed high adsorption capacities of 211.78, 197.13, and 195.69 mg/g for Pb(II) and 643.00, 577.80, and 567.10 mg/g for methylene blue (MB) in Yellow River water, Yangtze River water, and tap water, respectively. And the beads embedded with 43% RE could efficiently adsorb Pb(II) and MB with high capacities of 187.78 mg/g and 586.46 mg/g, respectively. This study provides a new route to design and develop a green, cost-effective, and efficient adsorbent for the decontamination of wastewater. Full article

(This article belongs to the Special Issue Novel Nanostructured Materials and Their Applications in Wastewater Treatment)

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12 pages, 6290 KiB

Open AccessEditor’s ChoiceArticle

Development of Au Nanoparticle Two-Dimensional Assemblies Dispersed with Au Nanoparticle-Nanostar Complexes and Surface-Enhanced Raman Scattering Activity

by Kosuke Sugawa, Kaichi Ono, Ritsurai Tomii, Yuka Hori, Yu Aoki, Koki Honma, Kaoru Tamada and Joe Otsuki

Nanomaterials 2024, 14(9), 764; https://doi.org/10.3390/nano14090764 - 26 Apr 2024

Viewed by 1036

Abstract

We recently found that polyvinylpyrrolidone (PVP)-protected metal nanoparticles dispersed in water/butanol mixture spontaneously float to the air/water interface and form two-dimensional assemblies due to classical surface excess theory and Rayleigh–Bénard–Marangoni convection induced by butanol evaporation. In this study, we found that by leveraging [...] Read more.

We recently found that polyvinylpyrrolidone (PVP)-protected metal nanoparticles dispersed in water/butanol mixture spontaneously float to the air/water interface and form two-dimensional assemblies due to classical surface excess theory and Rayleigh–Bénard–Marangoni convection induced by butanol evaporation. In this study, we found that by leveraging this principle, a unique structure is formed where hetero gold nanospheres (AuNPs)/gold nanostars (AuNSs) complexes are dispersed within AuNP two-dimensional assemblies, obtained from a mixture of polyvinylpyrrolidone-protected AuNPs and AuNSs that interact electrostatically with the AuNPs. These structures were believed to form as a result of AuNPs/AuNSs complexes formed in the water/butanol mixture floating to the air/water interface and being incorporated into the growth of AuNP two-dimensional assemblies. These structures were obtained by optimizing the amount of mixed AuNSs, with excessive addition resulting in the formation of random three-dimensional network structures. The AuNP assemblies dispersed with AuNPs/AuNSs complexes exhibited significantly higher Raman (surface-enhanced resonance Raman scattering: SERRS) activity compared to simple AuNP assemblies, while the three-dimensional network structure did not show significant SERRS activity enhancement. These results demonstrate the excellent SERRS activity of AuNP two-dimensional assemblies dispersed with hetero AuNPs/AuNSs complexes. Full article

(This article belongs to the Section Nanofabrication and Nanomanufacturing)

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13 pages, 3436 KiB

Open AccessEditor’s ChoiceArticle

Additive Manufacturing of Electrically Conductive Multi-Layered Nanocopper in an Air Environment

by David Pervan, Anil Bastola, Robyn Worsley, Ricky Wildman, Richard Hague, Edward Lester and Christopher Tuck

Nanomaterials 2024, 14(9), 753; https://doi.org/10.3390/nano14090753 - 25 Apr 2024

Viewed by 810

Abstract

The additive manufacturing (AM) of functional copper (Cu) parts is a major goal for many industries, from aerospace to automotive to electronics, because Cu has a high thermal and electrical conductivity as well as being ~10× cheaper than silver. Previous studies on AM [...] Read more.

The additive manufacturing (AM) of functional copper (Cu) parts is a major goal for many industries, from aerospace to automotive to electronics, because Cu has a high thermal and electrical conductivity as well as being ~10× cheaper than silver. Previous studies on AM of Cu have concentrated mainly on high-energy manufacturing processes such as Laser Powder Bed Fusion, Electron Beam Melting, and Binder Jetting. These processes all require high-temperature heat treatment in an oxygen-free environment. This paper shows an AM route to multi-layered microparts from novel nanoparticle (NP) Cu feedstocks, performed in an air environment, employing a low-power (<10 W) laser sintering process. Cu NP ink was deposited using two mechanisms, inkjet printing, and bar coating, followed by low-power laser exposure to induce particle consolidation. Initial parts were manufactured to a height of approximately 100 µm, which was achieved by multi-layer printing of 15 (bar-coated) to 300 (inkjetted) layers. There was no evidence of oxidised copper in the sintered material, but they were found to be low-density, porous structures. Nonetheless, electrical resistivity of ~28 × 10⁻⁸ Ω m was achieved. Overall, the aim of this study is to offer foundational knowledge for upscaling the process to additively manufacture Cu 3D parts of significant size via sequential nanometal ink deposition and low-power laser processing. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: New Trends in Inorganic Nanoparticles and Composites from Preparation to Applications)

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18 pages, 6275 KiB

Open AccessEditor’s ChoiceArticle

The Influence of the Mechanical Compliance of a Substrate on the Morphology of Nanoporous Gold Thin Films

by Sadi Shahriar, Kavya Somayajula, Conner Winkeljohn, Jeremy K. Mason and Erkin Seker

Nanomaterials 2024, 14(9), 758; https://doi.org/10.3390/nano14090758 - 25 Apr 2024

Viewed by 1035

Abstract

Nanoporous gold (np-Au) has found its use in applications ranging from catalysis to biosensing, where pore morphology plays a critical role in performance. While the morphology evolution of bulk np-Au has been widely studied, knowledge about its thin-film form is limited. This work [...] Read more.

Nanoporous gold (np-Au) has found its use in applications ranging from catalysis to biosensing, where pore morphology plays a critical role in performance. While the morphology evolution of bulk np-Au has been widely studied, knowledge about its thin-film form is limited. This work hypothesizes that the mechanical compliance of the thin film substrate can play a critical role in the morphology evolution. Via experimental and finite-element-analysis approaches, we investigate the morphological variation in np-Au thin films deposited on compliant silicone (PDMS) substrates of a range of thicknesses anchored on rigid glass supports and compare those to the morphology of np-Au deposited on glass. More macroscopic (10 s to 100 s of microns) cracks and discrete islands form in the np-Au films on PDMS compared to on glass. Conversely, uniformly distributed microscopic (100 s of nanometers) cracks form in greater numbers in the np-Au films on glass than those on PDMS, with the cracks located within the discrete islands. The np-Au films on glass also show larger ligament and pore sizes, possibly due to higher residual stresses compared to the np-Au/PDMS films. The effective elastic modulus of the substrate layers decreases with increasing PDMS thickness, resulting in secondary np-Au morphology effects, including a reduction in macroscopic crack-to-crack distance, an increase in microscopic crack coverage, and a widening of the microscopic cracks. However, changes in the ligament/pore widths with PDMS thickness are negligible, allowing for independent optimization for cracking. We expect these results to inform the integration of functional np-Au films on compliant substrates into emerging applications, including flexible electronics. Full article

(This article belongs to the Special Issue Design, Fabrication and Applications of Nanoporous Materials)

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34 pages, 15745 KiB

Open AccessEditor’s ChoiceArticle

A Systematic Genotoxicity Assessment of a Suite of Metal Oxide Nanoparticles Reveals Their DNA Damaging and Clastogenic Potential

by Silvia Aidee Solorio-Rodriguez, Dongmei Wu, Andrey Boyadzhiev, Callum Christ, Andrew Williams and Sabina Halappanavar

Nanomaterials 2024, 14(9), 743; https://doi.org/10.3390/nano14090743 - 24 Apr 2024

Viewed by 1034

Abstract

Metal oxide nanoparticles (MONP/s) induce DNA damage, which is influenced by their physicochemical properties. In this study, the high-throughput CometChip and micronucleus (MicroFlow) assays were used to investigate DNA and chromosomal damage in mouse lung epithelial cells induced by nano and bulk sizes [...] Read more.

Metal oxide nanoparticles (MONP/s) induce DNA damage, which is influenced by their physicochemical properties. In this study, the high-throughput CometChip and micronucleus (MicroFlow) assays were used to investigate DNA and chromosomal damage in mouse lung epithelial cells induced by nano and bulk sizes of zinc oxide, copper oxide, manganese oxide, nickel oxide, aluminum oxide, cerium oxide, titanium dioxide, and iron oxide. Ionic forms of MONPs were also included. The study evaluated the impact of solubility, surface coating, and particle size on response. Correlation analysis showed that solubility in the cell culture medium was positively associated with response in both assays, with the nano form showing the same or higher response than larger particles. A subtle reduction in DNA damage response was observed post-exposure to some surface-coated MONPs. The observed difference in genotoxicity highlighted the mechanistic differences in the MONP-induced response, possibly influenced by both particle stability and chemical composition. The results highlight that combinations of properties influence response to MONPs and that solubility alone, while playing an important role, is not enough to explain the observed toxicity. The results have implications on the potential application of read-across strategies in support of human health risk assessment of MONPs. Full article

(This article belongs to the Special Issue New Approach Methodologies for the Toxicity Assessment of Nanomaterials)

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21 pages, 2238 KiB

Open AccessEditor’s ChoiceSystematic Review

In Vitro Toxicological Insights from the Biomedical Applications of Iron Carbide Nanoparticles in Tumor Theranostics: A Systematic Review and Meta-Analysis

by Maria Antoniou, Georgia Melagraki, Iseult Lynch and Antreas Afantitis

Nanomaterials 2024, 14(9), 734; https://doi.org/10.3390/nano14090734 - 23 Apr 2024

Viewed by 977

Abstract

(1) Background: Despite the encouraging indications regarding the suitability (biocompatibility) of iron carbide nanoparticles (ICNPs) in various biomedical applications, the published evidence of their biosafety is dispersed and relatively sparse. The present review synthesizes the existing nanotoxicological data from in vitro studies relevant [...] Read more.

(1) Background: Despite the encouraging indications regarding the suitability (biocompatibility) of iron carbide nanoparticles (ICNPs) in various biomedical applications, the published evidence of their biosafety is dispersed and relatively sparse. The present review synthesizes the existing nanotoxicological data from in vitro studies relevant to the diagnosis and treatment of cancer. (2) Methods: A systematic review was performed in electronic databases (PubMed, Scopus, and Wiley Online Library) on December 2023, searching for toxicity assessments of ICNPs of different sizes, coatings, and surface modifications investigated in immortalized human and murine cell lines. The risk of bias in the studies was assessed using the ToxRTool for in vitro studies. (3) Results: Among the selected studies (n = 22), cell viability emerged as the most frequently assessed cellular-level toxicity endpoint. The results of the meta-analysis showed that cell models treated with ICNPs had a reduced cell viability (SMD = −2.531; 95% CI: −2.959 to −2.109) compared to untreated samples. A subgroup analysis was performed due to the high magnitude of heterogeneity (I² = 77.1%), revealing that ICNP concentration and conjugated ligands are the factors that largely influence toxicity (p < 0.001). (4) Conclusions: A dose-dependent cytotoxicity of ICNP exposure was observed, regardless of the health status of the cell, tested organism, and NP size. Inconsistent reporting of ICNP physicochemical properties was noted, which hinders comparability among the studies. A comprehensive exploration of the available in vivo studies is required in future research to assess the safety of ICNPs’ use in bioimaging and cancer treatment. Full article

(This article belongs to the Special Issue New Approach Methodologies for the Toxicity Assessment of Nanomaterials)

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12 pages, 1508 KiB

Open AccessEditor’s ChoiceArticle

Heteropolyacids@Silica Heterogeneous Catalysts to Produce Solketal from Glycerol Acetalization

by Catarina N. Dias, Isabel C. M. S. Santos-Vieira, Carlos R. Gomes, Fátima Mirante and Salete S. Balula

Nanomaterials 2024, 14(9), 733; https://doi.org/10.3390/nano14090733 - 23 Apr 2024

Viewed by 1043

Abstract

The composites of heteropolyacids (H₃PW₁₂, H₃PMo₁₂) incorporated into amine-functionalized silica materials were used for the first time as heterogeneous catalysts in the valorization of glycerol (a major waste from the biodiesel industry) through acetalization reaction [...] Read more.

The composites of heteropolyacids (H₃PW₁₂, H₃PMo₁₂) incorporated into amine-functionalized silica materials were used for the first time as heterogeneous catalysts in the valorization of glycerol (a major waste from the biodiesel industry) through acetalization reaction with acetone. The polyoxotungstate catalyst H₃PW₁₂@AptesSBA-15 exhibited higher catalytic efficiency than the phosphomolybdate, achieving 97% conversion and 97% of solketal selectivity, after 60 min at 25 °C, or 91% glycerol conversion and the same selectivity, after 5 min, performing the reaction at 60 °C. A correlation between catalytic performance and catalyst acidity is presented here. Furthermore, the stability of the solid catalyst was investigated and discussed. Full article

(This article belongs to the Special Issue Recent Developments in Nanochemistry for Heterogeneous Catalysis Advancements (2nd Edition))

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15 pages, 11880 KiB

Open AccessEditor’s ChoiceArticle

Epitaxial Growth of GaN Films on Chemical-Vapor-Deposited 2D MoS₂ Layers by Plasma-Assisted Molecular Beam Epitaxy

by Iwan Susanto, Hong-Shan Liu, Yen-Ten Ho and Ing-Song Yu

Nanomaterials 2024, 14(8), 732; https://doi.org/10.3390/nano14080732 - 22 Apr 2024

Viewed by 1146

Abstract

The van der Waals epitaxy of wafer-scale GaN on 2D MoS₂ and the integration of GaN/MoS₂ heterostructures were investigated in this report. GaN films have been successfully grown on 2D MoS₂ layers using three different Ga fluxes via a plasma-assisted [...] Read more.

The van der Waals epitaxy of wafer-scale GaN on 2D MoS₂ and the integration of GaN/MoS₂ heterostructures were investigated in this report. GaN films have been successfully grown on 2D MoS₂ layers using three different Ga fluxes via a plasma-assisted molecular beam epitaxy (PA-MBE) system. The substrate for the growth was a few-layer 2D MoS₂ deposited on sapphire using chemical vapor deposition (CVD). Three different Ga fluxes were provided by the gallium source of the K-cell at temperatures of 825, 875, and 925 °C, respectively. After the growth, RHEED, HR-XRD, and TEM were conducted to study the crystal structure of GaN films. The surface morphology was obtained using FE-SEM and AFM. Chemical composition was confirmed by XPS and EDS. Raman and PL spectra were carried out to investigate the optical properties of GaN films. According to the characterizations of GaN films, the van der Waals epitaxial growth mechanism of GaN films changed from 3D to 2D with the increase in Ga flux, provided by higher temperatures of the K-cell. GaN films grown at 750 °C for 3 h with a K-cell temperature of 925 °C demonstrated the greatest crystal quality, chemical composition, and optical properties. The heterostructure of 3D GaN on 2D MoS₂ was integrated successfully using the low-temperature PA-MBE technique, which could be applied to novel electronics and optoelectronics. Full article

(This article belongs to the Special Issue III-Nitride Semiconductors: Design, Characterization, Applications, and Devices)

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10 pages, 3353 KiB

Open AccessEditor’s ChoiceCommunication

Photoelectric Properties of GaS_1−xSe_x (0 ≤ x ≤ 1) Layered Crystals

by Yu-Tai Shih, Der-Yuh Lin, Bo-Chang Tseng, Ting-Chen Huang, Yee-Mou Kao, Ming-Cheng Kao and Sheng-Beng Hwang

Nanomaterials 2024, 14(8), 701; https://doi.org/10.3390/nano14080701 - 18 Apr 2024

Viewed by 920

Abstract

In this study, the photoelectric properties of a complete series of GaS_1−xSe_x (0 ≤ x ≤ 1) layered crystals are investigated. The photoconductivity spectra indicate a decreasing bandgap of GaS_1−xSe_x as the Se composition x [...] Read more.

In this study, the photoelectric properties of a complete series of GaS_1−xSe_x (0 ≤ x ≤ 1) layered crystals are investigated. The photoconductivity spectra indicate a decreasing bandgap of GaS_1−xSe_x as the Se composition x increases. Time-resolved photocurrent measurements reveal a significant improvement in the response of GaS_1−xSe_x to light with increasing x. Frequency-dependent photocurrent measurements demonstrate that both pure GaS crystals and GaS_1−xSe_x ternary alloy crystals exhibit a rapid decrease in photocurrents with increasing illumination frequency. Crystals with lower x exhibit a faster decrease in photocurrent. However, pure GaSe crystal maintains its photocurrent significantly even at high frequencies. Measurements for laser-power-dependent photoresponsivity and bias-voltage-dependent photoresponsivity also indicate an increase in the photoresponsivity of GaS_1−xSe_x as x increases. Overall, the photoresponsive performance of GaS_1−xSe_x is enhanced with increasing x, and pure GaSe exhibits the best performance. This result contradicts the findings of previous reports. Additionally, the inverse trends between bandgap and photoresponsivity with increasing x suggest that GaS_1−xSe_x-based photodetectors could potentially offer a high response and wavelength-selectivity for UV and visible light detection. Thus, this work provides novel insights into the photoelectric characteristics of GaS_1−xSe_x layered crystals and highlights their potential for optoelectronic applications. Full article

(This article belongs to the Special Issue 2D Materials and van der Waals Heterostructures for Optoelectronic Devices)

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25 pages, 6943 KiB

Open AccessEditor’s ChoiceArticle

Dependence of the Structural and Magnetic Properties on the Growth Sequence in Heterostructures Designed by YbFeO₃ and BaFe₁₂O₁₉

by Sondes Bauer, Berkin Nergis, Xiaowei Jin, Reinhard Schneider, Di Wang, Christian Kübel, Petr Machovec, Lukas Horak, Vaclav Holy, Klaus Seemann, Tilo Baumbach and Sven Ulrich

Nanomaterials 2024, 14(8), 711; https://doi.org/10.3390/nano14080711 - 18 Apr 2024

Cited by 1 | Viewed by 800

Abstract

The structure and the chemical composition of individual layers as well as of interfaces belonging to the two heterostructures M1 (BaFe₁₂O₁₉/YbFeO₃/YSZ) and M2 (YbFeO₃/BaFe₁₂O₁₉/YSZ) grown by pulsed laser deposition on yttria-stabilized [...] Read more.

The structure and the chemical composition of individual layers as well as of interfaces belonging to the two heterostructures M1 (BaFe₁₂O₁₉/YbFeO₃/YSZ) and M2 (YbFeO₃/BaFe₁₂O₁₉/YSZ) grown by pulsed laser deposition on yttria-stabilized zirconia (YSZ) substrates are deeply characterized by using a combination of methods such as high-resolution X-ray diffraction, transmission electron microscopy (TEM), and atomic-resolution scanning TEM with energy-dispersive X-ray spectroscopy. The temperature-dependent magnetic properties demonstrate two distinct heterostructures with different coercivity, anisotropy fields, and first anisotropy constants, which are related to the defect concentrations within the individual layers and to the degree of intermixing at the interface. The heterostructure with the stacking order BaFe₁₂O₁₉/YbFeO₃, i.e., M1, exhibits a distinctive interface without any chemical intermixture, while an Fe-rich crystalline phase is observed in M2 both in atomic-resolution EDX maps and in mass density profiles. Additionally, M1 shows high c-axis orientation, which induces a higher anisotropy constant K1 as well as a larger coercivity due to a high number of phase boundaries. Despite the existence of a canted antiferromagnetic/ferromagnetic combination (T < 140 K), both heterostructures M1 and M2 do not reveal any detectable exchange bias at T = 50 K. Additionally, compressive residual strain on the BaM layer is found to be suppressing the ferromagnetism, thus reducing the Curie temperature (Tc) in the case of M1. These findings suggest that M1 (BaFe₁₂O₁₉/YbFeO₃/YSZ) is suitable for magnetic storage applications. Full article

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24 pages, 4642 KiB

Open AccessEditor’s ChoiceArticle

Electrochemical Detection of Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺ with Sensors Based on Carbonaceous Nanomaterials and Fe₃O₄ Nanoparticles

by Ancuța Dinu (Iacob), Alexandra Virginia Bounegru, Catalina Iticescu, Lucian P. Georgescu and Constantin Apetrei

Nanomaterials 2024, 14(8), 702; https://doi.org/10.3390/nano14080702 - 18 Apr 2024

Viewed by 1045

Abstract

Two electrochemical sensors were developed in this study, with their preparations using two nanomaterials with remarkable properties, namely, carbon nanofibers (CNF) modified with Fe₃O₄ nanoparticles and multilayer carbon nanotubes (MWCNT) modified with Fe₃O₄ nanoparticles. The modified screen-printed [...] Read more.

Two electrochemical sensors were developed in this study, with their preparations using two nanomaterials with remarkable properties, namely, carbon nanofibers (CNF) modified with Fe₃O₄ nanoparticles and multilayer carbon nanotubes (MWCNT) modified with Fe₃O₄ nanoparticles. The modified screen-printed electrodes (SPE) were thus named SPE/Fe₃O₄-CNF and SPE/Fe₃O₄-MWCNT and were used for the simultaneous detection of heavy metals (Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺). The sensors have been spectrometrically and electrochemically characterized. The limits of detection of the SPE/Fe₃O₄-CNF sensor were 0.0615 μM, 0.0154 μM, 0.0320 μM and 0.0148 μM for Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺, respectively, and 0.2719 μM, 0.3187 μM, 1.0436 μM and 0.9076 μM in the case of the SPE/ Fe₃O₄-MWCNT sensor (following optimization of the working parameters). Due to the modifying material, the results showed superior performance for the SPE/Fe₃O₄-CNF sensor, with extended linearity ranges and detection limits in the nanomolar range, compared to those of the SPE/Fe₃O₄-MWCNT sensor. For the quantification of heavy metal ions Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺ with the SPE/Fe₃O₄-CNF sensor from real samples, the standard addition method was used because the values obtained for the recovery tests were good. The analysis of surface water samples from the Danube River has shown that the obtained values are significantly lower than the maximum limits allowed according to the quality standards specified by the United States Environmental Protection Agency (USEPA) and those of the World Health Organization (WHO). This research provides a complementary method based on electrochemical sensors for in situ monitoring of surface water quality, representing a useful tool in environmental studies. Full article

(This article belongs to the Special Issue Nanostructured Materials for the Assay of Organic/Inorganic Water Pollutants)

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20 pages, 1087 KiB

Open AccessEditor’s ChoiceArticle

Pump-Driven Opto-Magnetic Properties in Semiconducting Transition-Metal Dichalcogenides: An Analytical Model

by Habib Rostami, Federico Cilento and Emmanuele Cappelluti

Nanomaterials 2024, 14(8), 707; https://doi.org/10.3390/nano14080707 - 18 Apr 2024

Viewed by 715

Abstract

Single-layer transition-metal dichalcogenides provide an unique intrinsic entanglement between the spin/valley/orbital degrees of freedom and the polarization of scattered photons. This scenario gives rise to the well-assessed optical dichroism observed by using both steady and time-resolved probes. In this paper, we provide compact [...] Read more.

Single-layer transition-metal dichalcogenides provide an unique intrinsic entanglement between the spin/valley/orbital degrees of freedom and the polarization of scattered photons. This scenario gives rise to the well-assessed optical dichroism observed by using both steady and time-resolved probes. In this paper, we provide compact analytical modeling of the onset of a finite Faraday/Kerr optical rotation upon shining with circularly polarized light. We identify different optical features displaying optical rotation at different characteristic energies, and we describe in an analytical framework the time-dependence of their intensities as a consequence of the main spin-conserving and spin-flip processes. Full article

(This article belongs to the Special Issue Superconductivity and Magnetism in Two-Dimensional and Layered Materials)

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19 pages, 10539 KiB

Open AccessEditor’s ChoiceArticle

Elastic Liposomes Containing Calcium/Magnesium Ferrite Nanoparticles Coupled with Gold Nanorods for Application in Photothermal Therapy

by Ana Rita F. Pacheco, Ana Margarida Barros, Carlos O. Amorim, Vítor S. Amaral, Paulo J. G. Coutinho, Ana Rita O. Rodrigues and Elisabete M. S. Castanheira

Nanomaterials 2024, 14(8), 679; https://doi.org/10.3390/nano14080679 - 15 Apr 2024

Viewed by 952

Abstract

This work reports on the design, development, and characterization of novel magneto-plasmonic elastic liposomes (MPELs) of DPPC:SP80 (85:15) containing Mg_0.75Ca_0.25Fe₂O₄ nanoparticles coupled with gold nanorods, for topical application of photothermal therapy (PTT). Both magnetic and plasmonic [...] Read more.

This work reports on the design, development, and characterization of novel magneto-plasmonic elastic liposomes (MPELs) of DPPC:SP80 (85:15) containing Mg_0.75Ca_0.25Fe₂O₄ nanoparticles coupled with gold nanorods, for topical application of photothermal therapy (PTT). Both magnetic and plasmonic components were characterized regarding their structural, morphological, magnetic and photothermal properties. The magnetic nanoparticles display a cubic shape and a size (major axis) of 37 ± 3 nm, while the longitudinal and transverse sizes of the nanorods are 46 ± 7 nm and 12 ± 1.6 nm, respectively. A new methodology was employed to couple the magnetic and plasmonic nanostructures, using cysteine as bridge. The potential for photothermia was evaluated for the magnetic nanoparticles, gold nanorods and the coupled magnetic/plasmonic nanoparticles, which demonstrated a maximum temperature variation of 28.9 °C, 33.6 °C and 37.2 °C, respectively, during a 30 min NIR-laser irradiation of 1 mg/mL dispersions. Using fluorescence anisotropy studies, a phase transition temperature (T_m) of 35 °C was estimated for MPELs, which ensures an enhanced fluidity crucial for effective crossing of the skin layers. The photothermal potential of this novel nanostructure corresponds to a specific absorption rate (SAR) of 616.9 W/g and a maximum temperature increase of 33.5 °C. These findings point to the development of thermoelastic nanocarriers with suitable features to act as photothermal hyperthermia agents. Full article

(This article belongs to the Special Issue Preparation, Characterization, Properties, Simulation, and Applications of Nanostructured Materials)

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11 pages, 4030 KiB

Open AccessEditor’s ChoiceArticle

Non-Volatile Memory Based on ZnO Thin-Film Transistor with Self-Assembled Au Nanocrystals

by Hui Xie, Hao Wu and Chang Liu

Nanomaterials 2024, 14(8), 678; https://doi.org/10.3390/nano14080678 - 14 Apr 2024

Viewed by 1104

Abstract

Non-volatile memory based on thin-film transistor is crucial for system-on-panel and flexible electronic systems. Achieving high-performance and reliable thin-film transistor (TFT) memory still remains challenging. Here, for the first time, we present a ZnO TFT memory utilizing self-assembled Au nanocrystals with a low [...] Read more.

Non-volatile memory based on thin-film transistor is crucial for system-on-panel and flexible electronic systems. Achieving high-performance and reliable thin-film transistor (TFT) memory still remains challenging. Here, for the first time, we present a ZnO TFT memory utilizing self-assembled Au nanocrystals with a low thermal budget, exhibiting excellent memory performance, including a program/erase window of 9.8 V, 29% charge loss extrapolated to 10 years, and remarkable endurance characteristics. Moreover, the memory exhibits favorable on-state characteristics with mobility, subthreshold swing, and current on–off ratio of 17.6 cm²V⁻¹s⁻¹, 0.71 V/dec, and 10⁷, respectively. Our study shows that the fabricated TFT memory has great potential for practical applications. Full article

(This article belongs to the Special Issue Nanoelectronics: Materials, Devices and Applications)

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17 pages, 4906 KiB

Open AccessEditor’s ChoiceArticle

Sensing at the Nanoscale Using Nitrogen-Vacancy Centers in Diamond: A Model for a Quantum Pressure Sensor

by Hari P. Paudel, Gary R. Lander, Scott E. Crawford and Yuhua Duan

Nanomaterials 2024, 14(8), 675; https://doi.org/10.3390/nano14080675 - 12 Apr 2024

Viewed by 1259

Abstract

The sensing of stress under harsh environmental conditions with high resolution has critical importance for a range of applications including earth’s subsurface scanning, geological CO₂ storage monitoring, and mineral and resource recovery. Using a first-principles density functional theory (DFT) approach combined with [...] Read more.

The sensing of stress under harsh environmental conditions with high resolution has critical importance for a range of applications including earth’s subsurface scanning, geological CO₂ storage monitoring, and mineral and resource recovery. Using a first-principles density functional theory (DFT) approach combined with the theoretical modelling of the low-energy Hamiltonian, here, we investigate a novel approach to detect unprecedented levels of pressure by taking advantage of the solid-state electronic spin of nitrogen-vacancy (NV) centers in diamond. We computationally explore the effect of strain on the defect band edges and band gaps by varying the lattice parameters of a diamond supercell hosting a single NV center. A low-energy Hamiltonian is developed that includes the effect of stress on the energy level of a ±1 spin manifold at the ground state. By quantifying the energy level shift and split, we predict pressure sensing of up to 0.3 MPa/

\sqrt{Hz}

using the experimentally measured spin dephasing time. We show the superiority of the quantum sensing approach over traditional optical sensing techniques by discussing our results from DFT and theoretical modelling for the frequency shift per unit pressure. Importantly, we propose a quantum manometer that could be useful to measure earth’s subsurface vibrations as well as for pressure detection and monitoring in high-temperature superconductivity studies and in material sciences. Our results open avenues for the development of a sensing technology with high sensitivity and resolution under extreme pressure limits that potentially has a wider applicability than the existing pressure sensing technologies. Full article

(This article belongs to the Special Issue First-Principle Calculation Study of Nanomaterials)

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13 pages, 4189 KiB

Open AccessEditor’s ChoiceArticle

Multifunctional Vanadium Nitride-Modified Separator for High-Performance Lithium–Sulfur Batteries

by Sen Liu, Yang Liu, Xu Zhang, Maoqiang Shen, Xuesen Liu, Xinyue Gao, Linrui Hou and Changzhou Yuan

Nanomaterials 2024, 14(8), 656; https://doi.org/10.3390/nano14080656 - 10 Apr 2024

Cited by 1 | Viewed by 1298

Abstract

Lithium–sulfur batteries (LSBs) are recognized as among the best potential alternative battery systems to lithium-ion batteries and have been widely investigated. However, the shuttle effect has severely restricted the advancement in their practical applications. Here, we prepare vanadium nitride (VN) nanoparticles grown in [...] Read more.

Lithium–sulfur batteries (LSBs) are recognized as among the best potential alternative battery systems to lithium-ion batteries and have been widely investigated. However, the shuttle effect has severely restricted the advancement in their practical applications. Here, we prepare vanadium nitride (VN) nanoparticles grown in situ on a nitrogen-doped carbon skeleton (denoted as VN@NC) derived from the MAX phase and use it as separator modification materials for LSBs to suppress the shuttle effect and optimize electrochemical performance. Thanks to the outstanding catalytic performance of VN and the superior electrical conductivity of carbon skeleton derived from MAX, the synergistic effect between the two accelerates the kinetics of both lithium polysulfides (LiPSs) to Li₂S and the reverse reaction, effectively suppresses the shuttle effect, and increases cathode sulfur availability, significantly enhancing the electrochemical performance of LSBs. LSBs constructed with VN@NC-modified separators achieve outstanding rate performance and cycle stability. With a capacity of 560 mAh g⁻¹ at 4 C, it exhibits enhanced structural and chemical stability. At 1 C, the device has an incipient capacity of 1052.4 mAh g⁻¹, and the degradation rate averaged only 0.085% over 400cycles. Meanwhile, the LSBs also show larger capacities and good cycling stability at a low electrolyte/sulfur ratio and high surface-loaded sulfur conditions. Thus, a facile and efficient way of preparing modified materials for separators is provided to realize high-performance LSBs. Full article

(This article belongs to the Special Issue Nanomaterials for Lithium-Sulfur Batteries)

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25 pages, 5809 KiB

Open AccessEditor’s ChoiceArticle

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO₃ Nanoparticles

by Aleksandra Drozd-Rzoska, Joanna Łoś and Sylwester J. Rzoska

Nanomaterials 2024, 14(8), 655; https://doi.org/10.3390/nano14080655 - 9 Apr 2024

Cited by 1 | Viewed by 884

Abstract

The report presents static, low-frequency, and dynamic dielectric properties in the isotropic liquid, nematic, and solid phases of MBBA and related nanocolloids with paraelectric BaTiO₃ nanoparticles (spherical, d = 50 nm). MBBA (4-methoxybenzylidene-4′–butylaniline) is a liquid crystalline compound with a permanent dipole [...] Read more.

The report presents static, low-frequency, and dynamic dielectric properties in the isotropic liquid, nematic, and solid phases of MBBA and related nanocolloids with paraelectric BaTiO₃ nanoparticles (spherical, d = 50 nm). MBBA (4-methoxybenzylidene-4′–butylaniline) is a liquid crystalline compound with a permanent dipole moment transverse to the long molecular axis. The distortions-sensitive analysis of the dielectric constant revealed its hidden pretransitional anomaly, strongly influenced by the addition of nanoparticles. The evolution of the dielectric constant in the nematic phase shows the split into two regions, with the crossover coinciding with the standard melting temperature. The ‘universal’ exponential-type behavior of the low-frequency contribution to the real part of the dielectric permittivity is found. The critical-like pretransitional behavior in the solid phase is also evidenced. This is explained by linking the Lipovsky model to the Mossotti catastrophe concept under quasi-negative pressure conditions. The explicit preference for the ‘critical-like’ evolution of the apparent activation enthalpy is worth stressing for dynamics. Finally, the long-range, ‘critical-like’ behavior of the dissipation factor (D = tgδ), covering the isotropic liquid and nematic phases, is shown. Full article

(This article belongs to the Special Issue Current Research in Nematic Liquid Crystal Nanocomposites)

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