Search Results (95)

In this paper, the accelerated aging process of a layer of polymer composites based on the silicone rubber modified by plant-based fillers and iron carbonyl was investigated. The color change, Shore’s hardness, thermal resistance, and surface quality of the composites after weathering were tested. The degradation behavior of the silicone rubber and its composites was characterized by TGA and FTIR techniques, as well as optical microscopy. It was found that the aging process increased the hardness of the silicone rubber composites by approx. 10% compared to pure silicone, and by a further 10% by weight in the case of composites containing plant-based fillers, such as turmeric and goldenrod. The promising results indicate that a SR/CLP/Fe/AM composite modified with carbonyl iron and a surfactant acts as an effective stabilizer for the silicone rubber matrix. An increase in the maximum temperature of 40 °C was also recorded compared to the unmodified silicone rubber. The results showed that the surface color of the aged samples changed in terms of lightness and total color. It was found that silicone rubber composites containing plant-based fillers exhibit properties characteristic of age-resistant materials; in particular, the SR/CLP/Fe composites modified with carbonyl iron are more resistant to water and light during accelerated aging than unmodified silicone rubber, which ensures a longer service life. Full article

SiO₂ aerogels are promising candidates for energy-efficient glazing because of their low thermal conductivity and optical transparency; however, conventional formulations often fail to reconcile optical, thermal, and mechanical performance. This work aimed to resolve this bottleneck via controllable sol–gel synthesis and ambient pressure drying. Using methyltrimethoxysilane (MTMS) as the single silicon source, this study systematically explored the effects of alkaline catalyst type, water-to-MTMS ratio, and surfactant selection, and further developed an MTMS–dimethyl dimethoxy silicane (DMDMS) composite silicon source. Tetramethylammonium hydroxide (TMAOH) catalysis, a water-to-MTMS molar ratio of 7:1, and Pluronic F-127 (F127) surfactant yielded a uniform, hydrophobic aerogel with 93.50% porosity and 89.74% transmittance at 800 nm. The optimized composite system (MTMS:DMDMS = 9:1, 6 mL water, 2.0 g F127) enhanced compressive strength by 22.4% relative to pure MTMS aerogel, with 70.15% visible transmittance and thermal conductivity of 0.027 W/(m·K). These results demonstrate that multi-parameter formulation control can achieve a practical balance among mechanical robustness, optical transparency, and thermal insulation. This study provides a theoretical and process foundation for the engineering application of high-performance transparent thermal insulation materials. Full article

Constructing efficient conductive networks in flexible polymer matrices remains a central challenge in electromagnetic interference (EMI) shielding material design. In this work, a ‘point-line’ hybrid filler system combining conductive carbon black (CB) and multi-walled carbon nanotubes (MWCNTs) was incorporated into a silicone rubber matrix to systematically engineer the conductive network architecture. By optimising the CB/MWCNT blending ratio, a composite with a tensile strength of 8.5 MPa, elongation at break of 180%, and EMI shielding effectiveness of 50 dB was achieved at a 1:1 weight ratio. Further surface modification of the hybrid fillers using five surfactants, including sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), nonylphenol ethoxylate (NPEO), and octylphenol ethoxylate (OPEO), was systematically investigated. OPEO modification was proved the most effective, improving EMI shielding performance to 58 dB while enhancing tensile strength by 11.8% and elongation at break by 50%. These results demonstrate that rational filler hybridisation combined with targeted surfactant modification offers a practical and scalable route to high-performance flexible EMI shielding composites. Full article

In the present paper, In₂O₃ NPs were synthesized by a wet-chemical method, in the absence and presence of the surfactant, and deposited as thin films on silicon substrates. After deposition, the films were subjected to rapid thermal annealing (RTA) at 550 °C, 750 °C, and 900 °C, for 300 s, under an inert atmosphere. The correlation between the morphological, structural, and optical characteristics, the wetting capacity of In₂O₃ films synthesized under different synthesis conditions, and the influence of the RTA treatment are presented. The vibrations of In-O bonds for In₂O₃ samples were confirmed using FTIR spectroscopy. Structural analysis shows that In₂O₃ NPs have a cubic crystalline structure, but with the increase in temperature at 900 °C, diffraction peaks characteristic of the tetragonal phase of indium appear, correlated with a decrease in lattice parameters, as a result of the crystallinity. The morphology of the In₂O₃ samples was studied by SEM, revealing predominantly spherical and uniformly distributed particles with nanometric sizes. The absorption spectra of the In₂O₃ NPs showed peaks in the ultraviolet region, and the high energy bandgap value of the In₂O₃ films varied between 3.28 and 4.33 eV, depending on the samples and RTA treatment. The contact angle measurements of In₂O₃ films determined the wetting capacity of the surface, reflecting changes in surface morphology and structure induced by the RTA process. The results suggest that In₂O₃ thin films with spherical nanoparticles, good wettability, and percolation can be used for the development of sensors with increased selectivity and sensitivity. Full article

The threshold voltage (Vth) of p-GaN gate enhancement-mode (E-mode) high electron mobility transistors (HEMTs) on silicon substrates grown by metal–organic chemical vapor deposition (MOCVD) is often limited to 1.0–1.5 V. Apart from the low Mg acceptor activation rate, the non-uniform vertical Mg distribution in thin p-GaN layers is also a key bottleneck limiting Vth. This work reveals that the vertical distribution (not only magnitude) of Mg doping fundamentally influences Vth by modulating the charge centroid and electric field coupling to the heterointerface. Through bis(cyclopentadienyl)magnesium (Cp₂Mg) flow modulation, surfactant-assisted growth, and growth rate adjustment, the vertical Mg doping uniformity within the 80 nm p-GaN layer was improved while effectively suppressing Mg out-diffusion. A short-cycle gate-first self-aligned process was used to fabricate the devices, and the results showed that the improved Mg vertical distribution led to a significant Vth enhancement by 0.75 V. Technology Computer-Aided Design (TCAD) simulations further demonstrated that the uniform doping profile builds a stronger negative space charge field beneath the gate, raising the energy band and increasing Vth. This work not only presents practical strategies, but also establishes a direct physical link between vertical Mg doping distribution and Vth in Si-based E-mode HEMTs. Full article

Coal-bed gas well production is too low to realize a highly efficient exploitation of the #8 coal seam in the Shanxi formation in the Nalin region. Based on the reservoir characteristics, the designed poly-aromatic-grafted silicon-quantum-dot-based desorption agent (PQS) has been developed. Then, the adsorption/desorption behavior of CBM on the coal surface under the influence of this active chemical has been studied, and the synergy effect with an anionic–nonionic surfactant to desorption of CBM has also been discussed. The results show that the developed poly-aromatic-grafted silicon quantum dot, with a median size of 4.9 nm and +5.6 mV of zeta potential in neutral condition, has a significant emission peak with 470 nm at the excitation of 380 nm and 150,000 mg/L of salinity resistance, which also generates a strong adsorption capacity on the coal surface. A promoting effect to desorption of CBM for PQS nanofluid is exhibited and the Langmuir pressure is obviously increased. However, when the PQS nanofluid is synergized with an anionic–nonionic surfactant, the desorption of CBM is further improved and the wettability of the coal surface is altered from 78.2° to 84.2°. The desorption rate for this compound system reached 65.3%. It can be found that combining the quantum size, π–π stacking, π–π conjugation, and the synergy effect between PQS nanofluid and surfactant fluid with the traditional intermolecular force has a stronger capacity for promoting desorption of CBM than the conventional desorption agent. This study provides guidance for the molecular design of the desorption agent for deep coal rock and the application of silicon quantum dots. Full article

Droplet size is a key factor in minimizing spray drift. Different types of adjuvants and sprayer operating pressures can affect the droplet size distribution in various ways. This study aimed to evaluate the effects of commercial adjuvants, namely, acids and surfactant (AS), silicone surfactant (SS), organosilicone surfactant (OS), mineral oil (MO and MO₂), and copolymer (CP) adjuvants, on the droplet spectra and physicochemical properties of aqueous solutions. Hydrogen potential (pH), volumetric mass ($VM$), electrical conductivity (EC), surface tension (ST), contact angle (CA), and droplet spectra were measured. The droplet spectrum variables, including volumetric diameters ($D_{v0.1}$, $D_{v0.5}$, and $D_{v0.9}$), the Relative Span Factor ($RSF$), and percentages of the total volume of droplets with a diameter smaller than 100 µm (V100) and larger than 500 µm (V500), were determined using a laser diffraction particle analyzer (Malvern Spraytec). Spraying tests were carried out using the AXI 11003 flat fan nozzle at pressures of (0.1, 0.2, 0.3, 0.4, and 0.5) MPa. The increase in pressure increased the V100 and the $RSF$, with greater sensitivity observed for SS. Adjuvants such as AS, MO₂ and OS showed a more balanced trend, with a smaller increase in fine droplets and a greater reduction in coarse droplets. The principal component analysis (PCA) revealed that the droplet spectrum variables were the ones that best explained the variation among the solutions. A negative correlation was identified between EC and other physicochemical properties, such as pH, ST, and CA. Therefore, these properties alone did not determine the atomization pattern. The study demonstrates that optimizing spray quality and minimizing drift require a combined consideration of adjuvant physicochemical properties and their interaction with operational pressure. Full article

Prefilled syringes are valuable drug delivery systems, offering convenience and precision dosing. Among the critical factors influencing their performance is the stability of the silicone oil layer, which acts as a lubricant, guaranteeing the gliding properties of the plunger. The silicone oil, if it comes in contact with therapeutic formulations, can be subject to drug–container interactions, potentially leading to silicone oil release into the solution, thereby altering the gliding properties of the syringe and leading to unwanted particle formation, compromising drug efficacy and safety. Different measurement techniques, such as visual inspection, dynamic light scattering and spectroscopic analysis, are used to assess silicone oil layer stability in prefilled syringes. However, a quantitative, rapid and low-volume screening method to rapidly evaluate container compatibility for therapeutic formulations is not available. Here, we present a multi-well-based screening protocol allowing users to quantify, through fluorescence, the silicone oil released into a solution upon contact with liquid formulations. Fluorescently labeled uniform silicone oil layers of the desired thickness are deposited in glass-bottom wells and exposed to typical formulations, containing surfactants and monoclonal antibodies. The release of silicon oil as a function of contact time is quantified using fluorescence calibration. Beyond its use as a screening tool to evaluate drug–container compatibility, our protocol can contribute to the fundamental understanding of the factors and mechanisms influencing silicone oil layer stability and, furthermore, to the optimization of drug delivery systems. Full article

This study investigates the formation, physicochemical properties, and applicability of surfactant-free microemulsions (SFMEs) as nanoreactors for the synthesis of silicon dioxide nanoparticles. Surfactant-free systems offer a promising and environmentally benign alternative to traditional microemulsions in which particle formation is governed by surfactants, yet their structural behavior and synthesis mechanisms remain insufficiently understood. A ternary system composed of water, ethanol, and n-pentanol was selected as a model, and its structural organization was analyzed through electrical conductivity, surface tension, and dynamic light scattering (DLS) measurements. The results revealed a broad single-phase region, indicating high miscibility of the components and the formation of dynamically connected polar domains. Electrical conductivity data suggested gradual reorganization of the internal structure without a distinct percolation threshold, while surface tension analysis and the corresponding Gibbs free energies of aggregation (ΔG°) reflected a weaker thermodynamic driving force for aggregation compared to systems containing longer-chain alcohols. DLS measurements confirmed the presence of fluctuating aggregates with hydrodynamic radii between 30 and 85 nm, consistent with literature values for surfactant-free systems. Based on these findings, silica nanoparticles were synthesized within selected compositions of the single-phase region. The resulting particles exhibited predominantly spherical morphology and variable dispersity, reflecting the moderate structural stability of the underlying microemulsion. The synthesized silica nanoparticles typically ranged from approximately 0.9 to 1.2 μm in diameter, reflecting the structural characteristics of the selected SFME compositions. Overall, the results demonstrate that water/ethanol/n-pentanol SFMEs provide new insights into surfactant-free aggregation processes and offer a sustainable route for the synthesis of inorganic nanoparticles. Full article

Magnetorheological fluid exhibits shear-thinning behavior when subjected to high temperature environments exceeding 100 °C, which will significantly compromise the operational stability and reliability of the associated mechanical systems. To enhance the performance of magnetorheological fluid, this study selects soft magnetic particles, base carrier fluid, and surfactants based on their resistance to high temperatures and shear-thinning effects. A novel magnetorheological fluid with enhanced thermal stability and shear stability is subsequently developed by carefully selecting flake-shaped carbonyl iron powder, dimethyl silicone oil, and surfactant exhibiting both sedimentation stability and high temperature resistance. The apparent rheological properties and mechanical performance of the fluid are systematically evaluated. Experimental results indicate that the sedimentation rate of the prepared magnetorheological fluid is 3.86% after standing for 10 days, the thermal expansion rate at 200 °C is 12.8%, and the evaporation rate following repeated high temperature applications is only 0.66%. The shear yield stress of the prepared magnetorheological fluid is 31.2 kPa under the magnetic field of 817 mT. The prepared magnetorheological fluid demonstrates excellent thermal stability and shear-thinning resistance, which holds significant potential for enhancing the performance of magnetorheological devices in future applications. Full article

A modular strategy for the molecular design of silicone-based antifoaming agents was developed by precisely controlling the architecture of poly (methylhydrosiloxane) (PMHS). Sixteen PMHS variants were synthesized by systematically varying the siloxane chain length (L1–L4), backbone composition (D₃T₁ vs. D₃₀T₁), and terminal group chemistry (H- vs. M-type). These structural modifications resulted in a broad range of Si-H functionalities, which were quantitatively analyzed and correlated with defoaming performance. The PMHS matrices were integrated with high-viscosity PDMS, a nonionic surfactant, and covalently grafted fumed silica—which was chemically matched to each PMHS backbone—to construct formulation-specific defoaming systems with enhanced interfacial compatibility and colloidal stability. Comprehensive physicochemical characterization via FT-IR, ¹H NMR, GPC, TGA, and surface tension analysis revealed a nonmonotonic relationship between Si-H content and defoaming efficiency. Formulations containing 0.1–0.3 wt% Si-H achieved peak performance, with suppression efficiencies up to 96.6% and surface tensions as low as 18.9 mN/m. Deviations from this optimal range impaired performance due to interfacial over-reactivity or reduced mobility. Furthermore, thermal stability and molecular weight distribution were found to be governed by repeat unit architecture and terminal group selection. Compared with conventional EO/PO-modified commercial defoamers, the PMHS-based systems exhibited markedly improved suppression durability and formulation stability in high-viscosity environments. These results establish a predictive structure–property framework for tailoring antifoaming agents and highlight PMHS-based formulations as advanced foam suppressors with improved functionality. This study provides actionable design criteria for high-performance silicone materials with strong potential for application in thermally and mechanically demanding environments such as coating, bioprocessing, and polymer manufacturing. Full article

In this study, polymerized silicone surfactants were modified with polyether and tertiary amine groups with the aim of improving the surface performance. Various PSiEO/(PO)-OH(CH₃) surfactants were synthesized and their structures and performance were characterized through ¹H NMR, FTIR spectroscopy, static surface tension, dynamic surface tension, zeta potential, and dynamic light scattering measurements. Subsequently, the modified silicones were incorporated as surfactants in aqueous solutions with different pH values. The surfactants with different hydrophobic/hydrophilic groups and end-capping groups exhibited different surface performances over a wide pH range. Thermodynamic parameters indicated that the micellization and adsorption of these surfactants were endothermic and spontaneous processes driven by entropy. The processes were hindered by increasing the solution pH and modification with hydrophobic groups. The aggregation behavior was significantly different under acidic, neutral, and basic aqueous conditions. Full article

The atomic level polishing of a material surface affects the accuracy of devices and the application of materials. Silica slurries play an important role in chemical mechanical polishing (CMP) by polishing the material surface. In this study, an efficient and controllable Stöber approach was developed to synthesize uniform monodisperse silica spheres with different cationic surfactants. The obtained silica spheres exhibited a regular shape with a particle size of 50–150 nm and were distributed evenly and narrowly. The highest surface specific area of the silica spheres was approximately 1155.9 m²/g, which was conducive to the polish process. The monodisperse SiO₂ spheres were applied as abrasives in chemical mechanical polishing. The surface micrographs of silicon wafers during the CMP process were studied using atomic force microscopy (AFM). The results demonstrated that the surface roughness Ra values reduced from 1.07 nm to 0.979 nm and from 1.05 nm to 0.933 nm when using a CTAB-SiO₂ microsphere as an abrasive. These results demonstrate the advantages of monodisperse SiO₂ spheres as abrasive materials in chemical mechanical planarization processes. Full article

Agricultural spraying, despite modern technological advances, still poses the problem of downwind spray drift, which contributes to environmental contamination and ecological imbalance, which are critical sustainability concerns. This study investigated the effect of lateral wind on different unmanned aerial vehicle (UAV) spraying systems under semi-controlled conditions, additionally evaluating the impact of four tank-mix adjuvants (drift reduction agents (DRAs)) at varying concentrations on spray effectiveness, droplet size, and deposition compared to water as a control. By examining UAV-specific spray dynamics, this research provides insights into sustainable drift reduction strategies that minimize environmental impacts. For the UAV spraying performance trials, three UAVs with different spraying configurations were tested, TTA M6E, XAG XP2020, and DJI T30, to identify the most effective system for minimizing downwind spray drift. For the DRA effectiveness trials, four commercially available adjuvants were evaluated at different concentrations utilizing the T30 UAV, which was chosen because it produces the highest proportion of fine droplets. The DRA products included an ionic/non-ionic surfactant (DRA No. 1), silicone-based wetting agents (DRA Nos. 2 and 3), and a silicone-based spreader-adhesive (DRA No. 4). This study showed that, among the tested UAV spray systems, M6E and XP2020 performed better in low-wind conditions, while T30 was more suitable for stable target area deposition in windy conditions but produced higher quantities of fine droplets prone to drifting further. Lateral wind contributes significantly to spray drift, as shown by the results, with increased wind speed causing an additional drift of up to 2 m downwind for all systems. The study also showed that all the tested DRAs exhibit the potential to mitigate drift and improve crop coverage, contributing to more efficient resource use and reduced environmental impacts. All the DRA products either reduce the drift distance by up to 3 m or decrease the deposition by up to 67% compared to water. However, DRA No. 1 showed the best results out of all the tested products in terms of drift control, while DRA No. 4 showed the best target area coverage and adequate drift control capabilities. More field research is required to validate the effectiveness in real-life application scenarios. In summary, the following management measures can be used to control droplet drift using UAV spraying systems, in order of importance: selecting a UAV and nozzles that are optimal for the specific requirements of the spraying task, planning applications in correlation with lateral wind speed, and the use of DRAs. Full article

The photovoltaic (PV) industry is developing rapidly to support energy transformation and emission reduction. In the whole PV industry chain, diamond wire saw silicon powder (DWSSP) waste is the most promising secondary resource for recycling high-purity silicon. DWSSP mainly contains metal impurities, and the treatment process based on hydrometallurgy can effectively remove metal impurities. The current DWSSP recovery process was divided into three categories: direct acid leaching, pyrometallurgy followed by acid leaching, and acid leaching followed by pyrometallurgy. This paper gives a comprehensive overview of these three purification processes from the aspects of impurity removal and recovery yield. The results suggest that acid leaching followed by pyrometallurgy is currently the most effective process for removing metal impurities from DWSSP. Moreover, this study underscores the potential for enhancing the purity of reclaimed silicon through the application of external field reinforcement, oxygen-regulated acid leaching, and surfactant-facilitated organic acid leaching and points out the development direction for promoting silicon recovery from DWSSP. Full article