Search Results (72)

This study investigates spherical methyl silicone resin, a potentially environmentally friendly additive free of sulfur, phosphorus, and chlorine, as a lubricant additive in polyethylene glycol 200 (PEG 200) base oils. We evaluated concentration-response characteristics and tribological performance across PEG base oils containing 0.01–0.05 wt% resin. Tribological testing was conducted with a four-ball wear tester at 98 N and 1450 rpm for 30 min. All tested concentrations demonstrated excellent friction-reduction and anti-wear performance, with an optimal efficacy observed at 0.02 wt%. Surface characterization was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. This friction-reducing and anti-wear performance is attributed to the formation of silicon-oxygen species and graphene-like carbon structures, thereby effectively suppressing direct surface contact and mitigating wear. Consequently, spherical methyl silicone resin demonstrates considerable potential as a green lubricant additive for bearing steel applications. Full article

Drought frequently threatens the yield and quality of Carya cathayensis Sarg. cultivated in mountainous regions. To search for effective drought-resistant regulators is of great significance for alleviating short-term seasonal drought in C. cathayensis during dry seasons, thereby stabilizing its yield and quality. Silicon dioxide nanoparticles (SiO₂ NPs) mitigate abiotic stress in plants. To give insight into the regulatory role of SiO₂ NPs in mitigating drought stress, polyethylene glycol 6000 (PEG-6000) was used to simulate varying degrees of drought conditions, and the growth phenotype, photosynthetic physiological characteristics, antioxidant defense system, and cellular ultrastructure of C. cathayensis leaves were analyzed to evaluate the impacts of foliar-applied exogenous SiO₂ NPs. The results indicated that, compared with severe drought, 200 mg/L SiO₂ NP application to plants under severe drought treatment significantly increased superoxide dismutase and peroxidase activities and chlorophyll and nitrogen contents, while malondialdehyde levels decreased. Furthermore, SiO₂ NP application notably enhanced the net photosynthetic rate, stomatal conductance, and electron transport efficiency. This effectively alleviated both stomatal and non-stomatal limitations, thereby mitigating drought-induced photosynthetic inhibition. Additionally, Transmission electron microscopy revealed that SiO₂ NPs effectively preserved the structural integrity of chloroplasts, mitochondria, and nuclei, reducing drought-induced ultrastructural damage. In conclusion, exogenous SiO₂ NPs enhance drought tolerance in C. cathayensis by synergistically modulating photosynthesis, antioxidant defense, and cellular structural stability. Full article

Silicon (Si) plays a crucial role in mitigating biotic and abiotic stress in crops, yet its effects on cucumber seed germination under drought stress remain unclear. This study investigated the impact of exogenous Si on the ascorbic acid-glutathione (AsA-GSH) cycle during cucumber seed germination under PEG-6000-induced drought stress. Seeds of the cucumber cultivar ‘Xinchun No. 4’ were used in this study. Na₂SiO₃ served as the silicon source, and drought stress was simulated using PEG-6000. The treatments included distilled water (CK), 10% polyethylene glycol (PEG), and PEG combined with five concentrations of silicon (1, 3, 5, 7, and 9 mM Si). Results showed that 10% PEG significantly inhibited seed germination and reduced antioxidant capacity. In contrast, 5 mM Si (5.0 Si + PEG) alleviated PEG-induced stress, reducing malondialdehyde (MDA) and proline (Pro) by 36.87% and 13.71%, respectively, and decreasing reactive oxygen species (ROS) accumulation. Specifically, H₂O₂ and O₂·⁻ contents declined by 20.00–41.76% and 14.29–27.27%, respectively. The 5.0 Si + PEG treatment also reduced soluble sugar content by 29.08% and 27.84% at 48 h and 72 h, respectively, while increasing soluble protein content by 9.97% and 10.30% at 6 h and 12 h. Additionally, it enhanced activities of dehydroascorbate reductase (DHAR), glutathione reductase (GR), and glutathione Stransferase (GST) by 15.00%, 17.48%, and 18.81%, respectively, and elevated ascorbic acid (AsA) content and the GSH/GSSG ratio. In conclusion, 5 mM Si alleviated drought stress by activating the AsA-GSH cycle and enhancing antioxidant defense, providing valuable insights for Si application in agriculture. Full article

Gelcasting is a widely developed ceramic forming technique; however, a persistent challenge lies in the drying process, where cracking and deformation frequently occur, hindering the further development of gelcasting. In this study, a strategy was proposed to address warpage and cracking during drying through gel structure design, aimed at increasing the ultimate strain of the bodies. The stress–strain curves of the bodies were analyzed at the wet body, ethanol body, and dried body stages. The effects of different gels on the mechanical performance of the bodies and their roles in regulating drying stress were further examined. The incorporation of flexible polymer segments into the polyethylene glycol diglycidyl ether/polyethyleneimine (PEGDE/PEI) system enhanced the strain capacity of the bodies. A physically and chemically crosslinked gel, denoted as PEGDE/PEI-TAC/SMALA-Na (PPS), was designed and synthesized in a silicon carbide/carbon black aqueous slurry. This PPS gel imparted excellent mechanical properties to the bodies, manifested by high strain during the drying process and high strength after drying. These findings provide a new perspective for controlling the mechanical behavior of gelcast bodies through gel structure manipulation and achieving defect-free execution of the drying process in gelcasting. Full article

Microfluidic oxygenators promise to advance extracorporeal membrane oxygenation (ECMO) devices with enhanced hemodynamics and low prime volume. We are developing a silicon-based membrane oxygenator that will offer improved gas transfer and fluid flow control. Polyethylene glycol (PEG) has been used to improve hemocompatibility by providing excellent resistance to protein adsorption. Here, we characterized a polyethylene glycol surface modification of composite silicon–PDMS membranes to evaluate their effects on microfluidic oxygenator properties. X-ray photoelectron spectroscopy (XPS) and water contact angle goniometry confirmed successful PEG attachment, evidenced by the presence of characteristic C-O bonds and increased hydrophilicity, which was stable for 2 weeks. Oxygen flux tests demonstrated gas transfer rates as high as 89.6 ± 17.9 mL/min/m² and 50.8 ± 11.7 mL/min/m² for unmodified and PEG-coated membranes, respectively. Protein adsorption studies with human serum albumin (HSA) demonstrated a significant reduction in nonspecific protein binding on PEG-coated membranes with values as low as 14 ± 6 μg/cm². These studies expand on the characterization of our engineered oxygenator membranes and provide insight for the development of future surface optimization strategies to enhance hemocompatibility. Full article

Due to their visible photoluminescence (PL) at room temperature, porous silicon particles (PSps) have gained interest for their potential biomedical applications, making them promising biological markers for in vivo or in vitro use. This study explores the PL evolution and stabilization of PSps following a two-step oxidation process involving air annealing and chemical oxidation in deionized water. PS layers were fabricated by electrochemical etching of p⁺-Si wafers and then annealed in air at 300 °C and 600 °C for five minutes. The layers were then stored in deionized water and sonicated to produce PSps. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to analyze the morphology and composition of the particles, and spectrofluorimetry was used to monitor the PL over several weeks. Samples annealed at 300 °C exhibited a transition from nearly complete PL quenching to strong yellow–red emission. In contrast, the 600 °C sample showed no PL emission. The cytotoxicity of the PSps was evaluated using an MTT assay on human endothelial cells (EA.Hy926) with PSps and polyethylene glycol (PEG)-coated PSps at concentrations of (3.5–125 µg/mL) in both serum-free and fetal bovine serum (FBS)-containing media over 24, 48, and 72 h. Cell viability was significantly affected by both exposure time and particle concentration; however, this effect was prevented under conditions mimicking the physiological plasma environment. Full article

This study evaluated the effect of polyethylene glycol (PEG 1500 and 4000) addition on the enzymatic hydrolysis (EH) of ground rice husk (≤250 μm). To reduce the amount of enzyme adsorbed on silicon dioxide and lignin and to evaluate the enzymatic hydrolysis, PEG 1500 and 4000 g/mol were added at three concentrations (0.3, 0.4 and 0.5 g PEG/g SiO₂). When PEG 1500 was added at 0.5 g/g SiO₂, the conversion of cellulose to cellobiose was not significantly increased (p ≥ 0.05); the conversion to glucose was 41.76%, and the conversion of hemicellulose to xylose was 93.45%, all with respect to the control assay. Addition of PEG 4000 at 0.5 g/g SiO₂ showed an increase of 14.78% in the hydrolysis of cellulose to cellobiose, 56.59% in that of cellulose to glucose, and 93.24% in that of hemicellulose to xylose. The addition of PEG shows that at a higher molecular weight and higher concentration, there are significant differences in the percentage of conversion of cellulose and hemicellulose into fermentable sugars, achieving efficiencies of ≈75%. Full article

Lithium-ion batteries (LIBs) have become the dominant energy storage technology due to their versatility and superior performance across diverse applications. Silicon (Si) stands out as a particularly promising high-capacity anode material for next-generation LIBs, offering a theoretical capacity nearly ten times greater than conventional graphite anodes. However, its practical implementation faces a critical challenge: the material undergoes a ~300% volume expansion during lithiation/delithiation, which causes severe mechanical stress, electrode pulverization, and rapid capacity decay. In addressing these limitations, advanced polymer binders serve as essential components for preserving the structural integrity of Si-based anodes. Notably, self-healing polymeric binders have emerged as a groundbreaking solution, capable of autonomously repairing cycle-induced damage and significantly enhancing electrode durability. The evaluation of self-healing performance is generally based on mechanical characterization methods while morphological observations by scanning electron microscopy provide direct evidence of crack closure; for electrochemically active materials, electrochemical techniques including GCD, EIS, and CV are employed to monitor recovery of functionality. In this study, a novel self-healing copolymer (PHX-23) was synthesized for Si anodes using a combination of octadecyl acrylate (ODA), methacrylic acid (MA), 2-hydroxyethyl methacrylate (HEMA), and polyethylene glycol methyl ether methacrylate (PEGMA). The copolymer was thoroughly characterized using NMR, FTIR, TGA, SEM, and EDX to confirm its chemical structure, thermal stability, and morphology. Electrochemical evaluation revealed that the PHX-23 binder markedly improves cycling stability, sustaining a reversible capacity of 427 mAh g⁻¹ after 1000 cycles at 1C. During long-term cycling, the Coulombic efficiency of the PHX-23 polymer is 99.7%, and similar functional binders in the literature have shown similar results at lower C-rates. Comparative analysis with conventional binders (e.g., PVDF and CMC/SBR) demonstrated PHX-23’s exceptional performance, exhibiting higher capacity retention and improved rate capability. These results position PHX-23 as a transformative binder for silicon anodes in next-generation lithium-ion batteries. Full article

This study proposes a rigid-flexible neural optrode integrated with anti-bending SU-8 optical waveguides and locally soft peptide-functionalized microelectrodes to address the challenges of precise implantation and long-term biocompatibility in traditional neural interfaces. Fabricated via microelectromechanical systems (MEMS) technology, the optrode features a PBK/PPS/(PHE)₂ trilayer electrochemical modification that suppresses photoelectrochemical (PEC) noise by 63% and enhances charge storage capacity by 51 times. A polyethylene glycol (PEG)-enabled temporary rigid layer ensures precise implantation while allowing post-implantation restoration of flexibility and enabling positioning adjustment. In vitro tests demonstrate efficient light transmission through SU-8 waveguides in agar gel and a 63% reduction in PEC noise peaks. Biocompatibility analysis reveals that peptide-coated PI substrates improve cell viability by 32.5–37.1% compared to rigid silicon controls. In vivo validation in crucian carp midbrain successfully records local field potential (LFP) signals (60–80 μV), thereby confirming the optrode’s sensitivity and stability. This design provides a low-damage and high-resolution tool for neural circuit analysis. It also lays a technical foundation for future applications in monitoring neuronal activity and researching neurodegenerative diseases with high spatiotemporal resolution. Full article

Against the backdrop of global energy transition and strict environmental regulations, supercritical carbon dioxide (scCO₂) fracturing and oil displacement technologies have emerged as pivotal green approaches in shale gas exploitation, offering the dual advantages of zero water consumption and carbon sequestration. However, the inherent low viscosity of scCO₂ severely restricts its sand-carrying capacity, fracture propagation efficiency, and oil recovery rate, necessitating the urgent development of high-performance thickeners. The current research on scCO₂ thickeners faces a critical trade-off: traditional fluorinated polymers exhibit excellent philicity CO₂, but suffer from high costs and environmental hazards, while non-fluorinated systems often struggle to balance solubility and thickening performance. The development of new thickeners primarily involves two directions. On one hand, efforts focus on modifying non-fluorinated polymers, driven by environmental protection needs—traditional fluorinated thickeners may cause environmental pollution, and improving non-fluorinated polymers can maintain good thickening performance while reducing environmental impacts. On the other hand, there is a commitment to developing non-noble metal-catalyzed siloxane modification and synthesis processes, aiming to enhance the technical and economic feasibility of scCO₂ thickeners. Compared with noble metal catalysts like platinum, non-noble metal catalysts can reduce production costs, making the synthesis process more economically viable for large-scale industrial applications. These studies are crucial for promoting the practical application of scCO₂ technology in unconventional oil and gas development, including improving fracturing efficiency and oil displacement efficiency, and providing new technical support for the sustainable development of the energy industry. This study innovatively designed an amphiphilic modified amino silicone oil polymer (MA-co-MPEGA-AS) by combining maleic anhydride (MA), methoxy polyethylene glycol acrylate (MPEGA), and amino silicone oil (AS) through a molecular bridge strategy. The synthesis process involved three key steps: radical polymerization of MA and MPEGA, amidation with AS, and in situ network formation. Fourier transform infrared spectroscopy (FT-IR) confirmed the successful introduction of ether-based CO₂-philic groups. Rheological tests conducted under scCO₂ conditions demonstrated a 114-fold increase in viscosity for MA-co-MPEGA-AS. Mechanistic studies revealed that the ether oxygen atoms (Lewis base) in MPEGA formed dipole–quadrupole interactions with CO₂ (Lewis acid), enhancing solubility by 47%. Simultaneously, the self-assembly of siloxane chains into a three-dimensional network suppressed interlayer sliding in scCO₂ and maintained over 90% viscosity retention at 80 °C. This fluorine-free design eliminates the need for platinum-based catalysts and reduces production costs compared to fluorinated polymers. The hierarchical interactions (coordination bonds and hydrogen bonds) within the system provide a novel synthetic paradigm for scCO₂ thickeners. This research lays the foundation for green CO₂-based energy extraction technologies. Full article

Excessive Zn(II) ions in aquatic environments pose significant risks to both human health and ecological systems due to their toxic effects, bioaccumulation potential, and interference with essential biological processes. To address this issue, a novel analcime@calcium aluminate@polyethylene glycol 400 (ACP) nanocomposite was fabricated using the hydrothermal technique, alongside an analcime@calcium aluminate (AC) nanocomposite for the efficient elimination of Zn(II) ions from aqueous media. X-ray diffraction (XRD) analysis affirmed the successful formation of crystalline phases, revealing average crystallite sizes of 72.93 nm for AC and 63.60 nm for ACP. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the nanocomposites, showing that AC primarily contained oxygen, sodium, aluminum, silicon, and calcium, whereas ACP incorporated 19.3% carbon due to the polyethylene glycol 400. Field emission scanning electron microscopy (FE-SEM) revealed that AC exhibited hexagonal and platelet-like structures, whereas ACP displayed more dispersed and layered morphologies. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of stacked platelet-like structures in AC and more defined, separated nanosheets in ACP. The maximum adsorption capacities of AC and ACP were 149.93 and 230.95 mg/g, respectively. The adsorption pathway of Zn(II) ions onto ACP nanocomposite involved three primary interactions: electrostatic attraction facilitated by calcium aluminate, ion exchange provided by analcime, and complexation promoted by polyethylene glycol 400. Thermodynamic analysis indicated that the adsorption process was exothermic, spontaneous, and primarily chemical in nature. Kinetic modeling confirmed that adsorption followed the pseudo-second-order model, while isotherm studies demonstrated adherence to the Langmuir model, indicating monolayer adsorption on homogeneous sites. Full article

Cowpea is a nutritionally and economically valuable legume, known for its adaptability to adverse conditions. However, water stress negatively affects its development, requiring technologies to enhance resilience. This study aimed to induce tolerance to water deficit in cowpea through seed priming with polyethylene glycol 6000 (PEG 6000) and silicic acid. A completely randomized experiment was conducted in a phytotron chamber with two water regimes (W50 and W100) and six seed priming treatments, with four replications. Priming consisted of three water potentials induced by PEG 6000 (0 MPa, −0.4 MPa, and −0.8 MPa) and two silicon concentrations (0 and 200 mg L⁻¹). Gas exchange parameters, including photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), intercellular CO₂ concentration (Ci), instantaneous water use efficiency (WUEi), and instantaneous carboxylation efficiency (iCE), were evaluated. Seed priming with PEG 6000 and silicon improved A, WUEi, and iCE under water deficit. Treatments 2 (0 MPa + 200 mg L⁻¹ Si), 3 (−0.4 MPa + 0 mg L⁻¹ Si), and 4 (−0.4 MPa + 200 mg L⁻¹ Si) enhanced gas exchange, suggesting an effective strategy for improving drought tolerance in cowpea and ensuring food security. Full article

Rhodamine B dye is a hazardous pollutant that poses significant risks to human health and aquatic ecosystems due to its toxic, carcinogenic nature and high chemical stability. To address this issue, analcime@nickel orthosilicate nanocomposites were synthesized via the hydrothermal method for efficient rhodamine B dye removal. Two nanocomposites were synthesized: EW (without a template) and ET (with polyethylene glycol 400 as a template, followed by calcination at 600 °C for 5 h). X-ray diffraction (XRD) confirmed the formation of analcime (NaAlSi₂O₆) and nickel orthosilicate (Ni₂SiO₄), with crystallite sizes of 72.93 nm (EW) and 63.60 nm (ET). Energy-dispersive X-ray spectroscopy (EDX) showed distinct distributions of oxygen, sodium, aluminum, silicon, and nickel. Field-emission scanning electron microscopy (FE-SEM) revealed irregular morphology for EW and uniform spherical nanoparticles for ET. The maximum adsorption capacities (Q_max) were 174.83 mg/g for EW and 210.53 mg/g for ET. Adsorption followed the pseudo-second-order kinetic model and was best described by the Langmuir isotherm, indicating monolayer chemisorption. Thermodynamic studies showed that adsorption was exothermic (ΔH = −45.62 to −50.92 kJ/mol) and spontaneous (ΔG < 0) and involved an entropy increase (ΔS = +0.1441 to +0.1569 kJ/mol·K). These findings demonstrate the superior adsorption efficiency of the ET composite and its potential application in dye-contaminated wastewater treatment. Full article

Methylene blue dye, commonly used in various industries, poses significant risks to both human health and the environment due to its persistence, toxicity, and potential to disrupt aquatic ecosystems. Exposure can cause severe health conditions such as methemoglobinemia, while its stability and solubility allow it to persist in natural water systems, reducing oxygen levels and harming aquatic life. In this study, novel analcime/sodium magnesium aluminum silicon silicate nanocomposites (Z1 and Z2) were synthesized via a controlled hydrothermal method, where Z1 and Z2 were synthesized in the absence and presence of polyethylene glycol as a template, respectively. X-ray diffraction (XRD) analysis confirmed the formation of crystalline phases of analcime and sodium magnesium aluminum silicon silicate. The average crystallite size of the Z1 nanocomposite is 75.30 nm, whereas the Z2 nanocomposite exhibits a smaller average crystallite size of 60.27 nm due to the template effect. Field emission scanning electron microscopy (FE-SEM) revealed that Z2 exhibited more uniform and well-dispersed particles compared to Z1. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition, showing higher sodium content and optimized incorporation of aluminum and silicon in Z2. High-resolution transmission electron microscopy (HR-TEM) demonstrated that Z2 had well-defined spherical particles, indicating improved structural control. The maximum adsorption capacities were 230.95 mg/g for Z1 and 290.69 mg/g for Z2. The adsorption process was exothermic, spontaneous, and chemical in nature, following the pseudo-second-order kinetic model and Langmuir isotherm, confirming monolayer adsorption on homogeneous surfaces. Full article

Typical wet-chemical methods for the preparation of silica nanowires use polyvinylpyrrolidone and n-pentanol. This study presents a polyethylene glycol-based emulsion template method for the synthesis of SiO₂ nanowires (SiO₂NWs) in isopropanol. By systematically optimizing key parameters (type of solvent, polyethylene glycol molecular weight and dosage, dosage of sodium citrate, ammonium and tetraethyl orthosilicate, incubation temperature and time), SiO₂NWs with diameters about 530 nm were obtained. Replacing polyvinylpyrrolidone with polyethylene glycol enabled anisotropic growth in isopropanol, overcoming the dependency on traditional solvents like n-pentanol. Scale-up experiments (10× volume) demonstrated robust reproducibility, yielding nanowires with consistent morphology (~580 nm diameter). After calcination at 500 °C for 1 h, the morphology of the nanowires did not change significantly. Full article