Search Results (534)

Lead sulfide colloidal quantum dots (PbS QDs) have demonstrated great potential in short-wave infrared (SWIR) photodetectors due to their tunable bandgap, low cost, and broad spectral response. While significant progress has been made in surface ligand modification and defect state passivation, studies focusing on the interface between QDs and electrodes remain limited, which hinders further improvement in device performance. In this work, we propose an interface engineering strategy based on 3-aminopropyltriethoxysilane (APTES) to enhance the interfacial contact between PbS QD films and ITO interdigitated electrodes, thereby significantly boosting the overall performance of SWIR photodetectors. Experimental results demonstrate that the optimal 0.5 h APTES treatment duration significantly enhances responsivity by achieving balanced interface passivation and charge carrier transport. Moreover, The APTES-modified device exhibits a controllable dark current and faster photo-response under 1310 nm illumination. This interface engineering approach provides an effective pathway for the development of high-performance PbS QD-based SWIR photodetectors, with promising applications in infrared imaging, spectroscopy, and optical communication. Full article

Janus hydrogels, defined by their asymmetric architectures and bifunctional interfaces, have emerged as a transformative class of solid-state electrolytes in electrochemical energy storage. By integrating spatially distinct chemomechanical and ionic functionalities within a single matrix, they overcome the intrinsic limitations of conventional isotropic hydrogels, offering enhanced interfacial stability, directional ion transport, and dendrite suppression in lithium- and zinc-based batteries. This mini-review systematically highlights recent breakthroughs in Janus hydrogel design, including interfacial polymerization and layer-by-layer assembly, which collectively enable precise modulation of crosslinking gradients and ion transport pathways. This review uniquely frames Janus hydrogels from a battery-centric and interface-engineering perspective. It elucidates key structure–function correlations, identifies current limitations in scalable fabrication and electrochemical longevity, and outlines future directions toward intelligent, multifunctional platforms for next-generation flexible and biointegrated energy systems. Full article

The design of emulsions at the nanoscale is a significant application of nanotechnology. For spherical droplets and a given volume of dispersed phase, the nanometre size of droplets inversely increases the total area, $A={\displaystyle \frac{3V}{r}}$, allowing greater contact with organic and inorganic materials during application. In topical applications, not only is cell contact increased, but also permeability in the cell membrane. Nanoemulsions typically achieve kinetic stability rather than thermodynamic stability, so their commercial application requires reasonable resistance to flocculation and coalescence, which can be affected by temperature changes. Therefore, their thermoresponsive characterisation becomes relevant. In this work, we analyse this response in an O/W nanoemulsion of Palmarosa for antibacterial purposes that has already shown stability for one year at controlled room temperature. We now study hysteresis processes and the behaviour of the statistical distribution in droplet size by Dynamic Light Scattering, obtaining remarkable stability under temperature changes up to 50 °C. This includes a maintained chemical composition observed using Fourier Transform Infrared Spectroscopy and the preservation of antibacterial properties analysed through optical density tests on cultures and the Spread-Plate technique for bacteria colony counting. We obtain practically closed hysteresis curves for some tracers of droplet size distributions through controlled thermal cycles between 10 °C and 50 °C, exhibiting a non-linear behaviour in their distribution. In general, the results show notable physical, chemical, and antibacterial stability, suitable for commercial applications. Full article

This study presents the first quantitative comparison of catastrophic phase inversion behavior of water-in-oil emulsions stabilized by nanocrystalline cellulose (NCC) and molecular surfactants with different headgroup charge types: anionic (sodium dodecyl sulfate referred to as SDS), cationic (octadecyltrimethylammonium chloride referred to as OTAC), nonionic (C12–14 alcohol ethoxylate referred to as Alfonic), and zwitterionic (cetyl betaine referred to as Amphosol). By using conductivity measurements under controlled mixing and pendant drop tensiometry, this study shows that NCC markedly delays catastrophic phase inversion through interfacial jamming, whereas surfactant-stabilized systems exhibit concentration-dependent inversion driven by interfacial saturation. Specifically, NCC-stabilized emulsions exhibited a nonlinear increase in the critical aqueous phase volume fraction required for inversion, ranging from 0.253 (0 wt% NCC) to 0.545 (1.5 wt% NCC), consistent with enhanced resistance to inversion typically associated with the formation of rigid interfacial layers in Pickering emulsions. In contrast, surfactant-stabilized systems exhibited a concentration-dependent inversion trend with opposing effects. At low concentrations, limited interfacial coverage delayed inversion, while at higher concentrations, increased surfactant availability and interfacial saturation promoted earlier inversion and favored the formation of oil-in-water structures. Pendant drop tensiometry confirmed negligible surface activity for NCC, while all surfactants significantly lowered interfacial tension. Despite its weak surface activity, NCC imparted strong coalescence resistance above 0.2 wt%, attributed to steric stabilization. These findings establish distinct mechanisms for governing phase inversion in particle- versus surfactant-stabilized systems. To our knowledge, this is the first study to quantitively characterize the catastrophic phase inversion behavior of water-in-oil emulsions using NCC. This work supports the use of NCC as an effective stabilizer for emulsions with high internal phase volume. Full article

The effect of pH and temperature on the interaction of sodium citrate-coated magnetic iron oxide nanoparticles (IONPs) with the BSA protein was studied using optical methods. The optical properties of aqueous colloids of BSA, IONPs, and BSA with IONPs were studied with pH changes in the range of 2–12 and temperature in the range of 25–85 °C. It was found that at pH 2.0, no significant changes in the optical properties were observed with increasing temperature in aqueous colloids containing a mixture of BSA with IONPs. Temperature affects the optical properties of BSA colloids with IONPs in the pH range from 5.0 to 8.0. Moreover, by increasing the temperature at these pH levels, it is possible to control the particle size in the colloids. In general, both temperature and pH have a significant effect on the properties of the aqueous colloid of BSA with IONPs and allow for the control of interactions between BSA and IONPs, namely, the processes of aggregation, particle reclustering, and protein denaturation. Full article

Over the last decade, numerous impedance studies of the conductivity of suspensions containing colloidal (dielectric, semiconducting or metallic) particles have often led to the conclusion that the well-known Maxwell theory is insufficient to quantitatively explain the properties of these systems. We review some of the most characteristic results and show how the applicability of the Maxwell’s theory can be restored taking into account the adsorption phenomena occurring during AC impedance measurements in nanoparticle suspensions. The latter can drastically change the capacitance of the metal-electrolyte cell boundaries from the standard value, making it strongly dependent on the nanoparticle concentration. This factor significantly affects conductivity measurements through RC circuit characteristics. We present an analysis of available impedance measurement data of the dependence of conductivity on the nanoparticle concentration in this new paradigm. In order to emphasize the novelty and the acute sensitivity of ac-diagnosis to the presence of adsorption phenomena at the metal-electrolyte interface, direct adsorption determinations at such interfaces by using two modern experimental techniques are also presented. The main result of this work is the restoration of Maxwell’s theory, attributing the observed discrepancies to variations in cell conductance. Full article

The mean force between two highly like-charged macroions in the presence of monovalent counterions and added multivalent salt within solvents of varying dielectric constants was studied using Monte Carlo simulations. Without additional salt, the mean force is strongly repulsive at all macroion separations in solvents with a dielectric constant ${ϵ}_r$ ≥ 30. However, in solvents with ${ϵ}_r$≤ 30, macroions experience effective attraction, indicating that attractive interactions between highly charged macroions can occur even without multivalent salt in nonpolar solvents with low dielectric constants. The total multivalent counterion charge-to-total macroion charge ratio is defined as β which determines the amount of salt that is added to the system. At β = 0.075, the mean force becomes attractive at short separations in solvents with ${ϵ}_r$= 54 containing 1:3 salt, as well as in all solvents with 1:5 salt, while still exhibiting significant repulsion at longer separations. In contrast, for solvents with 1:3 salt and dielectric constants ${ϵ}_r$= 68 and ${ϵ}_r$= 78.4, the mean force turns attractive at a higher salt concentration, around β = 0.225. The shift in the mean force to an attractive state at short separations signifies charge inversion on the macroion surface when a sufficient amount of salt is present. At a stoichiometric ratio of multivalent counterions, long-range repulsion vanishes, and attraction becomes significant. However, with excess salt, the strength of the attractive mean force diminishes. Additionally, the attractive force at a given salt concentration increases as the dielectric constant decreases and is stronger in systems with 1:5 salt than in those with 1:3 salt. Full article

Introducing small-sized metal nanoparticles directly into biopolymers susceptible to thermal and chemical stimulations remains a significant challenge. Recently, we showed a novel approach to fabricating gold nanoparticles through pulsed laser ablation in liquid (PLAL) using a microchip laser (MCL). Despite its lower pulse energy compared to conventional lasers, this technique demonstrates high ablation efficiency, offering the potential to produce composites without compromising the distinctive structure of biopolymers. As a proof of concept, we successfully generated gelatin-stabilized gold nanoparticles with a smaller size (average diameter of approximately 4 nm), while preserving the unchanged circular dichroism (CD) spectra, indicating the retention of gelatin’s unique structure. Extending this technique to the preparation of type I collagen-stabilized gold nanoparticles yielded non-aggregated nanoparticles, although challenges in yield still persist. These results highlight the potential of the microchip laser ablation technique for producing metal nanoparticles within a vulnerable matrix. Full article

In this paper, the optical properties and lattice thermal conductivity of Ti₂AlB₂ were studied by first-principles calculations. The real part of the dielectric constant, ε₁, attains a significant value of 47.26 at 0.12 eV, indicating strong polarization capabilities and energy storage capacity. Regarding optical properties, Ti₂AlB₂ exhibits significant absorption peaks at photon energies of 4.19 eV, 6.78 eV, and 10.61 eV, and 14.32 eV, with absorption coefficients of 184,168.1 cm⁻¹, 228,860.8 cm⁻¹, 366,350.8 and 303,440.6 cm⁻¹, indicating a strong absorption capacity. The loss function exhibits peaks at 19.80 eV and the refractive index reaches a maximum of 8.30 at 0.01 eV. Reflectivity is notably higher in the 0–5 eV range, exceeding 44%, which demonstrates excellent reflective properties. This suggests that Ti₂AlB₂ has potential as an optical coating material across certain frequency bands. The lattice thermal conductivity of Ti₂AlB₂ is obtained at 27.2 W/(m·K). The phonon relaxation time is greater in the low-frequency region, suggesting that phonons have a longer duration of action during the heat transport process, which may contribute to higher thermal conductivity. Although the phonon group velocity is generally low, several factors influence thermal conductivity, including phonon relaxation time and Grüneisen parameters. The high Grüneisen parameter of Ti₂AlB₂ indicates strong anharmonic vibrations, which may enhance phonon scattering and consequently reduce thermal conductivity. However, Ti₂AlB₂ still exhibits some lattice thermal conductivity, suggesting that the contributions of phonon relaxation time and group velocity to its thermal conductivity may be more significant. The unique optical properties and thermal conductivity of Ti₂AlB₂ indicate its potential applications in optical coatings and high-temperature structural materials. Full article

The limited understanding of intermolecular interactions in deep eutectic solvents (DESs) has restricted their rational design and broader application. In this study, a series of hydrophobic DESs (HDESs) were prepared using lidocaine as the hydrogen bond acceptor and various carboxylic acids as hydrogen bond donors. Their physicochemical properties, including density, viscosity, and thermal stability, were systematically characterized. Interactions between components were evaluated through excess molar volume, viscosity deviation, and Grunberg–Nissan parameters. Strong hydrogen bonding between lidocaine and carboxylic acids was confirmed, which weakened with increasing alkyl chain length of the acids. Furthermore, as the acid content in the mixture increased, lidocaine’s ability to disrupt the intrinsic hydrogen-bonding network of the carboxylic acids decreased, thereby weakening the hydrogen bonding interactions between the components. The extraction capability of the HDESs for cobalt ions was evaluated in aqueous systems. Cobalt, a key material in lithium-ion batteries and advanced alloys, is in rising demand due to clean energy development. The lidocaine/decanoic acid (1:2) system exhibited nearly 100% extraction efficiency, surpassing conventional extractants. The hydrophobic nature of the HDESs facilitated effective phase separation and reduced solvent loss. These findings provide theoretical insights and design principles for developing high performance HDESs tailored for environmentally friendly metal recovery, particularly in battery recycling and treatment of industrial wastewater. Full article

The SAXS pattern and pore volume of SBA-15 are not affected by aging SBA-15 with water, dilute acetic acid, and ammonia up for to 1 month, while the specific surface area is substantially depressed in interactions with basic solutions. The SEM images indicate pits on the side surfaces of SBA-15 particles in interactions with basic solutions. Aging of SBA-15 in ammonia solutions results in cavities formed by the collapse of walls between neighboring hexagonal channels in the SBA-15. This phenomenon is discussed with a special emphasis on its possible effect on the potentiometric titration curves. Especially, a standard procedure, in which the SSA measured before the titration is used to calculate the σ₀, is compared with a modified procedure, in which the SSAs measured before and after the titration are used to estimate the SSA for each data point separately. Full article

The escalating industrial emissions have dramatically increased airborne particulate matter (PM), particularly submicron particles (PM0.3), creating substantial health risks through respiratory system penetration. Current fiber-based filtration systems predominantly relying on electrostatic adsorption mechanisms suffer from critical limitations, including insufficient efficiency, potential secondary contamination, and performance degradation in humid environments. We develop a flexible silica composite aerogel to overcome these challenges with customizable and exceptional superamphiphobicity. This composite aerogel exhibits high porosity of ~95% and robust compression Young’s modulus that reaches ~220 kPa at 50% strain even after 1000 cycles. These features enable it to maintain a high filtration efficiency of ~98.52% for PM0.3, even after 50 cycles under traditional artificial simulation conditions. Significantly, a competitive filtration efficiency of ~97.9% is still performed in our composite aerogel at high humidity (water mist), high temperatures (50–250 °C), and corrosive solutions or atmospheres environments, revealing potential industrial applications. This work is expected to replace conventional air filtration materials and pave the way for various human protection and industrial production applications. Full article

SnS_1−xSe_x (x = 0–1) films composed of vertically oriented nanosheet arrays were fabricated by vacuum thermal evaporation. The compositions of the SnS_1−xSe_x films were well tuned from SnS to SnSe, while their structures and morphology maintained the orthorhombic phase and the uniform nanosheet arrays. Se doping enhances the light absorption of the films, especially in the near-infrared region. The direct and indirect band gaps of the SnS_1−xSe_x (x = 0–1) nanosheet arrays films gradually changed from 1.26 eV and 1.12 eV for SnS to 1.00 eV and 0.79 eV for SnSe, respectively, with the change in compositions. The adjustable band gap makes these films promising candidates for infrared photodetectors and solar energy devices. Full article

Fine spodumene particles are challenging to treat by froth flotation and are often discarded. An approach to recover the lithium-bearing mineral is to selectively aggregate fine spodumene into larger sizes that are amenable to recovery by flotation. This research investigated the aggregation behaviour of spodumene and the gangue minerals K-feldspar and quartz, using commercially available anionic polyacrylamide flocculants. Calcium ions were used as activators that facilitated the selective adsorption of the carboxylate groups in the anionic flocculants onto the spodumene surface. The calcium ions decreased the magnitude of the negative zeta potential and reversed the zeta potential to positive for spodumene and K-feldspar, but not for quartz, below pH 10. Calcium concentrations of 312.5 g/t enhanced the adsorption of anionic polymers onto spodumene and K-feldspar, inducing aggregation, while quartz was aggregated only above 5000 g/t. Increasing the polymer concentration increased the aggregate size for spodumene and K-feldspar, but had little effect on quartz. In situ sizing and turbidity measurements indicated the optimal conditions for spodumene aggregation were 625 g/t of calcium and 63–84 g/t of the 58% anionic-charged polyacrylamide at pH 8.5. The sedimentation results showed limited separation due to quartz entrapment in the aggregates. Anionic polyacrylamide flocculants with calcium activators can aggregate fine spodumene particles. Full article

The evaporation of a blood sessile droplet on a solid substrate generates distinctive desiccation patterns. These patterns have been identified as a potential tool for interpreting the pathological information of donors, since their morphological features encode pathological indicators linked to blood-related disorders. We collected two representative sets of blood samples from anonymous patients: healthy donors (normal haematocrit) and anaemia patients (low haematocrit). Our real-time observations of the morphological evolution during desiccation reveal distinct differences in pattern development. The macroscopic analysis indicates that blood sessile droplets from anaemia patients with abnormally low haematocrit levels experience divergent morphological trajectories, forming cracking patterns distinguishable from those of healthy donors. Our microscopic comparisons show that the blood desiccation patterns of healthy donors exhibit a longer coronal region and greater deposit coverage in the central region than those of anaemia patients. Our further analysis correlates these morphological variations to the effects of the haematocrit level of blood samples on material redistribution. This work proposes a facile strategy for health diagnostics through blood desiccation pattern analysis, highlighting its potential as a foundation for diagnostic platforms. Full article