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Keywords = nanoparticles coalescence

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15 pages, 2397 KiB  
Article
A Double Closed-Loop Process for Nanoparticle Synthesis via Aerosol Mixing and Venturi Jet Scrubbing
by Bruno Fabiano, Marco Salerno, Marco Vocciante, Omar Soda and Andrea Pietro Reverberi
Appl. Sci. 2025, 15(14), 7693; https://doi.org/10.3390/app15147693 - 9 Jul 2025
Viewed by 274
Abstract
Inorganic nanoparticles (NPs) have been synthesised via mixing and coalescence of droplets containing precursors and entrained by gaseous streams. The droplets have been generated by ultrasonic aerosolisation of two different liquid phases, each containing the respective reagent. The as-produced NPs are trapped by [...] Read more.
Inorganic nanoparticles (NPs) have been synthesised via mixing and coalescence of droplets containing precursors and entrained by gaseous streams. The droplets have been generated by ultrasonic aerosolisation of two different liquid phases, each containing the respective reagent. The as-produced NPs are trapped by mixing with a liquid phase in a Venturi nozzle, acting simultaneously as a collector and concentrator of the solid nanosized phase produced. Commercial electrically powered ultrasonic aerosolising devices have been adapted to atomise salt solutions characterised by high electrical conductivity. This process allowed the synthesis of calcium carbonate NPs with an average diameter in the range of (34–52) nm, according to the concentration of precursors in the aerosolised phases. This closed-loop method of synthesis, where neither capping agents were used nor demanding operating conditions were adopted, can represent a safe and viable eco-friendly technique for NP production free of undesirable compounds, as required for pharmaceutical preparations and theranostic uses. Full article
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22 pages, 15268 KiB  
Article
Pickering Double Emulsions Stabilized with Chitin Nanocrystals and Myristic Acid-Functionalized Silica Nanoparticles for Curcumin and Chlorogenic Acid Co-Delivery
by Javier Paredes-Toledo, Javier Herrera, Javier Morales, Paz Robert, Joaquín Gómez-Estaca and Begoña Giménez
Pharmaceutics 2025, 17(4), 521; https://doi.org/10.3390/pharmaceutics17040521 - 16 Apr 2025
Cited by 1 | Viewed by 2726
Abstract
Background/Objectives: Double emulsions (DEs) enable the simultaneous encapsulation of water-soluble and oil-soluble bioactive compounds. Their stability can be enhanced through Pickering stabilization, where solid particles are irreversibly anchored at the interfaces, forming a steric barrier. This study aimed to evaluate the release [...] Read more.
Background/Objectives: Double emulsions (DEs) enable the simultaneous encapsulation of water-soluble and oil-soluble bioactive compounds. Their stability can be enhanced through Pickering stabilization, where solid particles are irreversibly anchored at the interfaces, forming a steric barrier. This study aimed to evaluate the release behavior of curcumin and chlorogenic acid (CA) in Pickering DEs formulated with chitin nanocrystals (ChNCs) stabilizing the outer interface (DE-ChNC) and both ChNCs and myristic acid-functionalized silica nanoparticles (SNPs-C14) stabilizing the outer and inner interfaces (DE-ChNC-C14) under in vitro gastrointestinal digestion. Methods: The optimal homogenization parameters (time and speed) for stabilizing the external interface with ChNCs were determined using a statistical design. Pickering DEs were characterized (droplet size and size distribution, microstructure, creaming, encapsulation efficiency and stability, rheological behavior) and subjected to the INFOGEST digestion method. Results: ChNCs effectively maintained the droplet size, microstructure, and ζ-potential, preventing coalescence and creaming while enhancing viscosity and gel-like behavior, contributing to improved physical stability. The CA encapsulation efficiency was higher in DE-ChNC-C14 (91.4%) than in DE-ChNC (45.0%) due to the presence of SNPs-C14 at the inner interface, which improved CA retention during storage. CA was gradually released from DE-ChNC-C14 throughout digestion, with bioaccessibility similar to that of the control DE (stabilized with conventional emulsifiers; ~60%). Curcumin bioaccessibility in the Pickering DEs was relatively high (~40%) but lower than in the control DE, as the ChNCs reduced lipid digestion and curcumin bioaccessibility. Conclusions: ChNCs and SNPs-C14 effectively stabilized the outer and inner interfaces of DEs, enabling the simultaneous release of water-soluble and oil-soluble bioactives with health benefits. Full article
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21 pages, 5908 KiB  
Article
The Role of Polyisobutylene-Bis-Succinimide (PIBSI) Dispersants in Lubricant Oils on the Deposit Control Mechanism
by Erhan Özdemir, Esra Kan, Binbin Guo, Eugene Pashkovski, Anil Agiral and Erol Yildirim
Polymers 2025, 17(8), 1041; https://doi.org/10.3390/polym17081041 - 11 Apr 2025
Viewed by 1022
Abstract
Molecular modeling calculations for the design and improvement of next-generation additives for motor oils have reached a level that can support and improve experimental results. The regulation of insoluble sludge nanoparticle aggregations within oil and on engine pistons is a critical performance metric [...] Read more.
Molecular modeling calculations for the design and improvement of next-generation additives for motor oils have reached a level that can support and improve experimental results. The regulation of insoluble sludge nanoparticle aggregations within oil and on engine pistons is a critical performance metric for lubricant oil additives. There is a general agreement regarding the mechanism of deposit formation which is attributed to the self-aggregation of nano-sized carbon rich insoluble structures. Dispersants are a primary category of additives employed to inhibit aggregation in lubricant formulations. Along with the base oil, they are crucial in dispersing and stabilizing insoluble particles to manage the formation of deposits. In this study, multiscale modeling methods were used to elucidate molecular mechanism of deposit control via polyisobutylene-bis-succinimide (PIBSI) dispersants by using density functional theory (DFT), molecular dynamics (MD) simulations of cells constructed by statistical sampling of molecular configurations, and coarse-grained (CG) simulations. The aim of this study was to understand the role of different groups such as succinimide, amine center, and two polyisobutylene (PIB) tails in PIBSI dispersants. It was demonstrated that the mechanism of deposit control by the polymer-based PIBSI dispersant can be elucidated through the interactions among various constituents, including hydrogen bonding and hydrophilic–hydrophobic interactions. We showed that sludge type nanoparticle aggregation is mitigated by intercalation of polar amine central groups of dispersant between the nanoparticles followed by the extension of two hydrophobic PIB chains into the oil phase that decreases coalesce further by forming a hydrophobic repulsive layer. Full article
(This article belongs to the Section Polymer Applications)
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25 pages, 8004 KiB  
Article
Facile Synthesis and Characterization of Novel Fe0.65Mg0.35Cr2O4@C Nanocomposite for Efficient Removal of Cd(II) Ions from Aqueous Media
by Ehab A. Abdelrahman, Reem K. Shah, Mortaga M. Abou-Krisha, Fawaz A. Saad and Alaa M. Munshi
Inorganics 2025, 13(3), 82; https://doi.org/10.3390/inorganics13030082 - 12 Mar 2025
Cited by 6 | Viewed by 805
Abstract
Cd(II) ions pose significant environmental and health threats due to their extreme toxicity, persistence, and bioaccumulation in ecosystems. They are associated with severe health disorders such as bone damage, kidney failure, and carcinogenic effects and disrupt aquatic life by impairing enzymatic and reproductive [...] Read more.
Cd(II) ions pose significant environmental and health threats due to their extreme toxicity, persistence, and bioaccumulation in ecosystems. They are associated with severe health disorders such as bone damage, kidney failure, and carcinogenic effects and disrupt aquatic life by impairing enzymatic and reproductive processes. In this research, novel Fe0.65Mg0.35Cr2O4@C nanocomposites, synthesized using the Pechini sol–gel method at 600 °C (F600) and 800 °C (F800), were investigated for their efficacy in removing Cd(II) ions from aqueous media. FE-SEM analysis showed that F600 had agglomerated spherical nanoparticles with an average grain size of 45.71 nm and a relatively porous structure, while F800 displayed denser and more compact spherical nanoparticles with an average grain size of 73.65 nm. HR-TEM images confirmed these findings, showing that F600 nanoparticles were loosely arranged with an average particle diameter of 14.72 nm, whereas F800 exhibited larger, more aggregated particles with an average diameter of 59.22 nm, reflecting enhanced particle coalescence at higher temperatures. EDX analysis confirmed the elemental composition of both samples, with F600 containing higher carbon content (7.0%) compared to F800 (3.4%), attributed to the more complete combustion of organic precursors during F800’s synthesis. This difference in composition, along with the structural variations, influenced their adsorption performance. F600 demonstrated superior adsorption with a maximum capacity of 295.86 mg/g compared to F800’s 185.19 mg/g. Thermodynamic and kinetic analyses confirmed that the adsorption was exothermic, spontaneous, and governed by a physical mechanism following the pseudo-second-order model and Langmuir isotherm. The superior performance of F600 is attributed to its higher surface area, porosity, and smaller particle size, which enhance the availability of active adsorption sites. Full article
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15 pages, 5399 KiB  
Article
Studies on Morphological Evolution of Gravure-Printed ZnO Thin Films Induced by Low-Temperature Vapor Post-Treatment
by Giuliano Sico, Vincenzo Guarino, Carmela Borriello and Maria Montanino
Nanomaterials 2024, 14(24), 2006; https://doi.org/10.3390/nano14242006 - 13 Dec 2024
Viewed by 1087
Abstract
In recent years, the morphology control of semiconductor nanomaterials has been attracting increasing attention toward maximizing their functional properties and reaching their end use in real-world devices. However, the development of easy and cost-effective methods for preparing large-scale patterned semiconductor structures on flexible [...] Read more.
In recent years, the morphology control of semiconductor nanomaterials has been attracting increasing attention toward maximizing their functional properties and reaching their end use in real-world devices. However, the development of easy and cost-effective methods for preparing large-scale patterned semiconductor structures on flexible temperature-sensitive substrates remains ever in demand. In this study, vapor post-treatment (VPT) is investigated as a potential, simple and low-cost post-preparative method to morphologically modify gravure-printed zinc oxide (ZnO) nanoparticulate thin films at low temperatures. Exposing nanoparticles (NPs) to acidic vapor solution, spontaneous restructuring pathways are observed as a consequence of NPs tending to reduce their high interfacial energy. Depending on the imposed environmental conditions during the treatment (e.g., temperature, vapor composition), various ZnO thin-film morphologies are produced, from dense to porous ones, as a result of the activation and interplay of different spontaneous interface elimination mechanisms, including dissolution–precipitation, grain boundary migration and grain rotation–coalescence. The influence of VPT on structural/optical properties has been examined via XRD, UV–visible and photoluminescence measurements. Controlling NP junctions and network nanoporosity, VPT appears as promising cost-effective, low-temperature and pressureless post-preparative platform for preparing supported ZnO NP-based films with improved connectivity and mechanical stability, favoring their practical use and integration in flexible devices. Full article
(This article belongs to the Section Physical Chemistry at Nanoscale)
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32 pages, 1410 KiB  
Article
Modeling the Production of Nanoparticles via Detonation—Application to Alumina Production from ANFO Aluminized Emulsions
by Pedro M. S. Santos, Belmiro P. M. Duarte, Nuno M. C. Oliveira, Ricardo A. L. Mendes, José L. S. A. Campos and João M. C. Silva
Modelling 2024, 5(4), 1642-1673; https://doi.org/10.3390/modelling5040086 - 7 Nov 2024
Viewed by 1049
Abstract
This paper investigates the production of nanoparticles via detonation. To extract valuable knowledge regarding this route, a phenomenological model of the process is developed and simulated. This framework integrates the mathematical description of the detonation with a model representing the particulate phenomena. The [...] Read more.
This paper investigates the production of nanoparticles via detonation. To extract valuable knowledge regarding this route, a phenomenological model of the process is developed and simulated. This framework integrates the mathematical description of the detonation with a model representing the particulate phenomena. The detonation process is simulated using a combination of a thermochemical code to determine the Chapman–Jouguet (C-J) conditions, coupled with an approximate spatially homogeneous model that describes the radial expansion of the detonation matrix. The conditions at the C-J point serve as initial conditions for the detonation dynamic model. The Mie–Grüneisen Equation of State (EoS) is used, with the “cold curve” represented by the Jones–Wilkins–Lee Equation of State. The particulate phenomena, representing the formation of metallic oxide nanoparticles from liquid droplets, are described by a Population Balance Equation (PBE) that accounts for the coalescence and coagulation mechanisms. The variables associated with detonation dynamics interact with the kernels of both phenomena. The numerical approach employed to handle the PBE relies on spatial discretization based on a fixed-pivot scheme. The dynamic solution of the models representing both processes is evolved with time using a Differential-Algebraic Equation (DAE) implicit solver. The strategy is applied to simulate the production of alumina nanoparticles from Ammonium Nitrate Fuel Oil aluminized emulsions. The results show good agreement with the literature and experience-based knowledge, demonstrating the tool’s potential in advancing understanding of the detonation route. Full article
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14 pages, 3327 KiB  
Article
Tuning the Interfacial Deformation of Gliadin-Flaxseed Gum Complex Particles for Improving the Foam Stability
by Ping Wu, Wei Shang, Jiaqi Shao, Qianchun Deng, Jisong Zhou, Xia Xiang, Dengfeng Peng and Weiping Jin
Gels 2024, 10(11), 677; https://doi.org/10.3390/gels10110677 - 22 Oct 2024
Viewed by 1214
Abstract
Gliadin nanoparticle (GNP) is a promising foaming agent, but its application is hindered by the limited foam stability under low acidic conditions. Herein, we attempted to tune the foam stability of GNP by coating it with flaxseed gum (FG) and investigated the structure, [...] Read more.
Gliadin nanoparticle (GNP) is a promising foaming agent, but its application is hindered by the limited foam stability under low acidic conditions. Herein, we attempted to tune the foam stability of GNP by coating it with flaxseed gum (FG) and investigated the structure, interfacial behaviors, and foam functionality of gliadin-FG (GFG) particles at pH 4.5. Results showed that the formation of GFG complex particles was driven by an electrostatic interaction between positive charge patches on the surface of GNP (~17 mV) and negative charges in FG molecule (~−13 mV) at all tested ratios. The addition of appropriate amounts of FG (1:0.05) effectively improved the foam stability of GNP. This was because GFG with larger sizes and lower surface charge possessed higher rigidity after coating with FG. When they adsorbed at the air/water interface, their deformation process was slower than that of GNP, as indicated by interfacial dilatational rheology and cryo-SEM, and the covered particles seemed to be more closely distributed to form solid-like and dense interfacial films. Notably, the addition of FG at a higher ratio (1:0.3) promoted the foam stability of GNP by about five folds because the larger GFG with suitable flexibility and wettability could form a stiff interface layer with more significant elastic response, and the unabsorbed particles and FG could form a gel-like network structure in the continuous phase. These characteristics effectively prevented foam disproportionation and coalescence, as well as retard the drainage. Our findings demonstrate that coating GNPs with FG is an effective approach to improve their application in foamed foods. Full article
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12 pages, 7313 KiB  
Article
Morphological Characteristics of W/Cu Composite Nanoparticles with Complex Phase Structure Synthesized via Reactive Radio Frequency (RF) Thermal Plasma
by Chulwoong Han, Song-Yi Kim, Soobin Kim and Ji-Woon Lee
Metals 2024, 14(9), 1070; https://doi.org/10.3390/met14091070 - 18 Sep 2024
Cited by 1 | Viewed by 967
Abstract
The W/Cu binary system is characterized by its mutual insolubility and excellent wettability, making W/Cu composite materials ideal for managing thermal and electrical properties in electronic components. To optimize material properties, control over the microstructure is crucial, and nanocomposites with uniform dispersion offer [...] Read more.
The W/Cu binary system is characterized by its mutual insolubility and excellent wettability, making W/Cu composite materials ideal for managing thermal and electrical properties in electronic components. To optimize material properties, control over the microstructure is crucial, and nanocomposites with uniform dispersion offer significant advantages. In this study, W/Cu composite nanoparticles were synthesized by feeding a blended feedstock of tungsten trioxide (WO3) micro-powder and cupric oxide (CuO) micro-powder into a reactive radio frequency (RF) argon–hydrogen thermal plasma system. Cu-coated W nanocomposite particles were obtained through the vaporization, reduction, and condensation processes. The resulting nanocomposite particles were composed of body-centered cubic (BCC) α-W, A15 β-W, and face-centered cubic (FCC) Cu phases, with a chemical composition closely matching theoretical calculations. The phase evolution and morphological changes of the synthesized particles were analyzed as a function of heat treatment temperatures up to 1000 °C in a reducing atmosphere. Up to 600 °C, the phase composition and morphology remained stable. At 800 °C, localized diffusion and coalescence of Cu led to the formation of particulate Cu, and a significant phase transformation from metastable β-W to α-W was observed. Additionally, extensive Cu segregation due to long-range diffusion resulted in distinct Cu-rich and Cu-depleted regions. In these regions, notable sintering of W particles and the complete disappearance of β-W occurred. The results showed that the temperature-dependent redistribution of Cu plays a crucial role in the phase transformation of W and the morphology of W/Cu composite particles. Full article
(This article belongs to the Section Metallic Functional Materials)
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19 pages, 11975 KiB  
Article
Enhancing Performance and Sustainability of Engine Lubricants and Biolubricants by Dispersing SiO2 Nanoparticles Coated with KH570-Silane Coupling Agent
by Homeyra Piri, Massimiliano Renzi and Marco Bietresato
Appl. Sci. 2024, 14(17), 7943; https://doi.org/10.3390/app14177943 - 5 Sep 2024
Cited by 6 | Viewed by 1657
Abstract
One of the technical possibilities to enhance the properties of lubricants and biolubricants is dispersing nanoparticles in them. Although conceptually simple, this operation faces challenges related to: (1) obtaining an initial good dispersion of the nanoparticles in the liquid and (2) ensuring the [...] Read more.
One of the technical possibilities to enhance the properties of lubricants and biolubricants is dispersing nanoparticles in them. Although conceptually simple, this operation faces challenges related to: (1) obtaining an initial good dispersion of the nanoparticles in the liquid and (2) ensuring the stability of this dispersion to avoid coalescence. The objective of this study is to verify possible improvements of the stability and characteristics of conventional and bio-based lubricants by efficiently dispersing in them surface-modified SiO2 nanoparticles. The silane coupling agent KH570 was utilized to modify the surface properties of SiO2 nanoparticles, facilitating their dispersion within the lubricants. Nanolubricants and nanobiolubricants were prepared using a two-step technique. The dispersion stability of these lubricants was assessed using sedimentation photography, FTIR, and UV-Vis spectrophotometric analyses. The addition of SiO2 nanoparticles resulted in enhanced physicochemical properties of the resulting lubricant, including slight increases in density and viscosity, as well as a higher viscosity index. Chemical analyses, such as TAN and TBN measurements, confirmed that the nanoparticle addition at various concentrations (0.25%, 0.5%, 0.75%, and 1.0%) did not introduce critical acidity levels or compromise the alkaline reserve. ICP-OES analysis indicated minimal impact on essential additive concentrations, supporting the feasibility of SiO2 nanoparticles in enhancing lubricant properties without destabilizing additives. The stability of the nanolubricants was monitored over 77 days, with visible sedimentation beginning around the 30th day and becoming more pronounced by the 54th and 77th days. Bio-lubricants exhibited slightly higher sedimentation than conventional lubricants. Optimizing the sonication time proved to be crucial, with longer sonication times (2.5 h) significantly improving the stability of nanolubricants across various concentrations of added nanoparticles. FTIR analysis confirmed the presence of SiO2 and KH570, indicating no alteration to the basic functional structures of the lubricants and biolubricants. UV-Vis spectrophotometry further underscored the importance of optimizing sonication time for enhanced stability. Overall, this study demonstrates that incorporating surface-modified SiO2 nanoparticles enhances the properties and stability of conventional and biolubricants, offering potential for improved performance in industrial and engine applications. Full article
(This article belongs to the Section Nanotechnology and Applied Nanosciences)
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14 pages, 5876 KiB  
Article
Ultrasound Control of Pickering Emulsion-Based Capsule Preparation
by Filip Ratajczak, Bassam Jameel, Rafał Bielas and Arkadiusz Józefczak
Sensors 2024, 24(17), 5710; https://doi.org/10.3390/s24175710 - 2 Sep 2024
Viewed by 1260
Abstract
Capsules with microparticle shells became of great interest due to their potential in many fields. Those capsules can be fabricated at high temperatures from particle-stabilized emulsions (Pickering emulsions) by sintering together particles that cover droplets. One of the problems with such an approach [...] Read more.
Capsules with microparticle shells became of great interest due to their potential in many fields. Those capsules can be fabricated at high temperatures from particle-stabilized emulsions (Pickering emulsions) by sintering together particles that cover droplets. One of the problems with such an approach is accurately controlling whether particles are already sintered and creating the rigid capsule shell of a capsule. Here, we propose using a non-destructive ultrasound method for monitoring Pickering emulsion-based capsules prepared using heating under an alternating magnetic field. The polyethylene microparticles that were responsive to temperatures higher than 112 °C were used as droplet stabilizers together with iron oxide nanoparticles. During the coalescence of the droplets, facilitated by an external electric field, the ultrasonic attenuation increased, giving evidence that the ultrasound method detects structural changes in Pickering emulsions. The main change was the difference in the droplets’ size, which was also observed via optical microscopy. The attenuation of ultrasound increased even more when measured after magnetic heating for the same concentration of particle stabilizers. Simultaneously, the values of ultrasonic velocity did not exhibit similar variety. The results show that the values of the attenuation coefficient can be used for a quantitative evaluation of the capsule formation process. Full article
(This article belongs to the Section Physical Sensors)
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18 pages, 3322 KiB  
Article
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
Cited by 2 | Viewed by 1444
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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14 pages, 6599 KiB  
Article
An Amphiphilic Surface with Improved Thermal Radiation for Water Harvesting
by Han Wang, Shengtao Li, Ye Zhang, Weihui Wu, Khaled Abdeen Mousa Ali and Changyou Li
Molecules 2024, 29(11), 2672; https://doi.org/10.3390/molecules29112672 - 5 Jun 2024
Viewed by 1377
Abstract
Water scarcity poses a significant challenge for people living in arid areas. Despite the effectiveness of many bioinspired surfaces in promoting vapor condensation, their water-harvesting efficiency is insufficient. This is often exacerbated by overheating, which decreases the performance in terms of the micro-droplet [...] Read more.
Water scarcity poses a significant challenge for people living in arid areas. Despite the effectiveness of many bioinspired surfaces in promoting vapor condensation, their water-harvesting efficiency is insufficient. This is often exacerbated by overheating, which decreases the performance in terms of the micro-droplet concentration and movement on surfaces. In this study, we used a spotted amphiphilic surface to enhance the surfaces’ water-harvesting efficiency while maintaining their heat emissivity. Through hydrophilic particle screening and hydrophobic groove modifying, the coalescence and sliding characteristics of droplets on the amphiphilic surfaces were improved. The incorporation of boron nitride (BN) nanoparticles further enhanced the surfaces’ ability to harvest energy from condensation. To evaluate the water-harvesting performance of these amphiphilic surfaces, we utilized a real-time recording water-harvesting platform to identify microscopic weight changes on the surfaces. Our findings indicated that the inclusion of glass particles in hydrophobic grooves, combined with 1.0 wt.% BN nanoparticles, enhanced the water-harvesting efficiency of the amphiphilic surfaces by more than 20%. Full article
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11 pages, 8664 KiB  
Article
Optical Characteristics of Directly Deposited Gold Nanoparticle Films
by Jordi Sancho Parramon, Tilen Švarc, Peter Majerič, Žiga Jelen and Rebeka Rudolf
Surfaces 2024, 7(2), 369-379; https://doi.org/10.3390/surfaces7020023 - 27 May 2024
Viewed by 1464
Abstract
The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4 [...] Read more.
The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by the Ultrasonic Spray Pyrolysis (USP) technology. Four samples were produced, with AuNP deposition times on the glass substrate of 15 min, 30 min, 1 h and 4 h. The morphological characterisation of the deposited films showed that the size of the first deposited AuNPs was between 10 and 30 nm, while, with a longer duration of the deposition process, larger clusters of AuNPs grew by coalescence and aggregation. The prepared layers were characterised optically with Ultraviolet–visible spectroscopy (UV–vis) and ellipsometry. The ellipsometric measurements showed an increasingly denser and thicker effective thickness of the AuNP layers. The extinction spectra displayed a clear local surface plasmonic resonance (LSPR) signature (peak 520–540 nm), indicating the presence of isolated particles in all the samples. For all AuNP layers, the imaginary part of the parallel and perpendicular components of the anisotropic dielectric function was dominated by a central peak at around 2.2 eV, corresponding to the LSPR of isolated particles, and a high-energy shoulder due to Au interband transitions. It was shown that, as the density of particles increased, the extinction cross-section grew over the whole spectral range where measurements are taken. Thus, the response can be explained with an enhanced electromagnetic response between the AuNPs that can be connected to the increase in particle density, but also by the formation of clusters and irregular structures. Full article
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11 pages, 2160 KiB  
Communication
A Uni-Micelle Approach for the Controlled Synthesis of Monodisperse Gold Nanocrystals
by Liangang Shan, Wenchao Wang, Lei Qian, Jianguo Tang and Jixian Liu
Nanomaterials 2024, 14(11), 900; https://doi.org/10.3390/nano14110900 - 21 May 2024
Cited by 3 | Viewed by 1696
Abstract
Small-size gold nanoparticles (AuNPs) are showing large potential in various fields, such as photothermal conversion, sensing, and medicine. However, current synthesis methods generally yield lower, resulting in a high cost. Here, we report a novel uni-micelle method for the controlled synthesis of monodisperse [...] Read more.
Small-size gold nanoparticles (AuNPs) are showing large potential in various fields, such as photothermal conversion, sensing, and medicine. However, current synthesis methods generally yield lower, resulting in a high cost. Here, we report a novel uni-micelle method for the controlled synthesis of monodisperse gold nanocrystals, in which there is only one kind micelle containing aqueous solution of reductant while the dual soluble Au (III) precursor is dissolved in oil phase. Our synthesis includes the reversible phase transfer of Au (III) and “uni-micelle” synthesis, employing a Au (III)-OA complex as an oil-soluble precursor. Size-controlled monodisperse AuNPs with a size of 4–11 nm are synthesized by tuning the size of the micelles, in which oleylamine (OA) is adsorbed on the shell of micelles and enhances the rigidity of the micelles, depressing micellar coalescence. Monodisperse AuNPs can be obtained through a one-time separation process with a higher yield of 61%. This method also offers a promising way for the controlled synthesis of small-size alloy nanoparticles and semiconductor heterojunction quantum dots. Full article
(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles: 2nd Edition)
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17 pages, 11586 KiB  
Article
Humic Polyelectrolytes Facilitate Rapid Microwave Synthesis of Silver Nanoparticles Suitable for Wound-Healing Applications
by Yu Zhang, Konstantin S. Larionov, Simeng Zhang, Nikita A. Sobolev, Andrey I. Konstantinov, Dmitry S. Volkov, Evgeniya V. Suslova, Vladimir E. Chernov, Anton I. Poloskov, Ruslan I. Glushakov and Irina V. Perminova
Polymers 2024, 16(5), 587; https://doi.org/10.3390/polym16050587 - 21 Feb 2024
Cited by 7 | Viewed by 2029
Abstract
This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes—humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and [...] Read more.
This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes—humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and leonardite and one sodium fulvate isolated from natural brown water seeped through peat deposits were used in this study. The dynamics of the growth rate of AgNPs was characterised by UV–VIS spectroscopy by measuring the intensity of surface plasmon resonance at 420 nm. Transmission electron microscopy was used to characterise the size and morphology of AgNPs. Dynamic light scattering was used to determine size distributions of the synthesised AgNPs in the solutions. It was established that both conventional and microwave syntheses assisted with the coal humates produced small-size AgNPs in the range from 4 to 14 nm, with the maximum share of particles with sizes of (6 ± 2) nm by TEM estimates. The peat fulvate yielded much larger NPs with sizes from 10 to 50 nm by TEM estimates. DLS measurements revealed multimodal distributions of AgNPs stabilised with HS, which included both single NPs with the sizes from 5 to 15 nm, as well as their dominating aggregates with sizes from 20 to 200 nm and a smaller portion of extra-large aggregates up to 1000 nm. The given aggregates were loosely bound by humic polyelectrolyte, which prevented the coalescence of AgNPs into larger particles, as can be seen in the TEM images. The significant acceleration in the reaction time—a factor of 60 to 70—was achieved with the use of MW irradiation: from 240 min down to 210–240 s. The coal humate stabilised AgNPs showed antimicrobial properties in relation to S. aureus. A conclusion was made regarding the substantial advantages of microwave synthesis in the context of time and scaling up for the large-scale production of AgNP-HS preparations with antimicrobial properties suitable for external wound-healing applications. Full article
(This article belongs to the Special Issue Advances in Polyelectrolytes and Polyelectrolyte Complexes)
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