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Facile spraying fabrication of highly flexible and mechanically robust superhydrophobic F-SiO <sub/>2</sub> @PDMS coatings for self-cleaning and drag-reduction applications
摘要： Superhydrophobic coatings treated as surface functional materials are endowed with great application potential with respect to self-cleaning, drag-reduction, anti-icing, etc. In this study, we fabricated a highly flexible and mechanically robust superhydrophobic F-SiO2@PDMS coating through a facile layer-by-layer strategy. It was demonstrated that PDMS played a crucial role of binder for immobilizing the F-SiO2 nanoparticles and improving their adhesion to substrate materials. Meanwhile, the PDMS layer endowed the superhydrophobic coating with superior mechanical flexibility. Finally, the as-constructed superhydrophobic coating exhibited excellent water-repellency with a high water contact angle of 156.5° and low sliding angle of only 2.0°. Furthermore, the water adhesion strength on the superhydrophobic coating was only 2 mN, indicating its ultralow viscous resistance to dynamic moving water droplets. The superhydrophobic F-SiO2@PDMS coating was independent of the substrates without any limitations, and they exhibited high flexibility and mechanical robustness with the elongation ratio reaching 83.3% under the conditions of high superhydrophobicity. Also, the superhydrophobic coating exhibited strong durability under the severe environments of corrosion and mechanical abrasion. Thus, the as-fabricated highly flexible and mechanically robust superhydrophobic F-SiO2@PDMS coating is considered to be an ideal candidate for applications in the fields of self-cleaning and drag-reduction.
关键词： F-SiO2@PDMS,drag-reduction,mechanical robustness,superhydrophobic coatings,self-cleaning
更新于2025-09-04 15:30:14
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Preparation of Nano-SiO2/Al2O3/ZnO-Blended PVDF Cation-Exchange Membranes with Improved Membrane Permselectivity and Oxidation Stability
摘要： Ion exchange membranes are used in practically every industry; however, most of them have defects such as low permeability and poor oxidation resistance. In this paper, cation-exchange membranes were prepared with poly (vinylidene fluoride) (PVDF) blended with nano-SiO2, nano-Al2O3 and nano-ZnO. Sulfonic acid groups were injected into the membrane prepared by styrene grafting and sulfonation. The methods used for characterizing the prepared membranes were Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electrochemical measurements. Membrane performance, such as the ion exchange capacity (IEC), water uptake (WU), transport number, membrane permselectivity, membrane resistance, functional groups, and morphology were also evaluated. The hydrophilia, IEC, and permselectivity of cation-exchange membranes depended on the nanoparticle content of the membrane matrix. High transport property values were obtained, which increased with increasing nano-SiO2/Al2O3/ZnO weight fractions. Finally, the cation-exchange membranes prepared with 1.5% nano-SiO2, 2.0% nano-Al2O3 or 2.0% nano-ZnO all exhibited excellent membrane properties, including membrane permselectivity (PVDF/2% ZnO-g-PSSA membranes, 94.9%), IEC (PVDF/2% Al2O3-g-PSSA membranes, 2.735 mmol·g?1), and oxidation resistance (PVDF/1.5% SiO2-g-PSSA membranes, 2.33%). They can be used to separate applications in a variety of different areas, such as water treatment, electro-driven separation, heavy metal smelting, or other electrochemical processes.
关键词： cation-exchange membrane,nano-SiO2/Al2O3/ZnO,poly(vinylidene fluoride),membrane performance
更新于2025-09-04 15:30:14
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Improvement of photocatalyst properties of magnetic NPs by new anionic surfactant
摘要： In this research, Fe3O4 NPs was synthesized by co- precipitation approach. Then SiO2 shell was grown on the Fe3O4 core. Synthesized NPs were characterized by means of XRD, FTIR, VSM, TGA, SEM and TEM. The magnetic properties of core and core-shell NPs was 74 and 42 emu/g, respectively. The TEM picture of core-shell was showed thickness shell of SiO2 on the Fe3O4 NPs. The size of this shell about 2.5nmWhich caused the core magnetic property to be well preserved. Photocatalyst activity of the synthesized NPs was investigated by using methyl orange (MO) and methylene blue (MB) as pollutant at different pH. For first time sodium citrate was used to improvement photo- degradation. The Fe3O4 indicated good photocatalyst activity for photo-degradation and it’s activity was considerably increased after SiO2 shell growth.
关键词： Fe3O4@SiO2,Photocatalyst,Tri sodium citrate,Fe3O4,Anionic surfactant
更新于2025-09-04 15:30:14
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Charge and Coordination Directed Liposome Fusion onto SiO2 and TiO2 Nanoparticles
摘要： TiO2 and SiO2 are very useful materials for building biointerfaces. A particular interesting aspect is their interactions with lipid bilayers. Many past research efforts focused on phosphocholine (PC) lipids, which form supported lipid bilayers (SLB) on SiO2 at physiological conditions but are adsorbed as intact liposomes on TiO2. Low pH was required to form PC SLBs on TiO2. This work intends to understand the surface forces and chemistry responsible for such differences. Two charge neutral lipids: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 2-((2,3-bis(oleoyloxy)propyl)dimethylammonio)ethyl ethyl phosphate (DOCPe); and two negatively charged lipids: 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) and 2-((2,3-bis(oleoyloxy)propyl)dimethylammonio)ethyl hydrogen phosphate (DOCP) were used. Using calcein leakage assays, adsorption measurement, cryo-TEM, and washing, we concluded that charge is the dominating factor on SiO2. The two neutral lipids form SLB on SiO2 at pH 3 and 7, but the two negatively charged ones cannot form. On TiO2, both charge and coordination chemistry are important. The two anionic lipids formed SLB from pH 3 to 10. DOCP had stronger affinity than DOPS likely due to the tighter terminal phosphate binding of the former. The two neutral liposomes formed SLB only at pH 3, where phosphate interaction and van der Waals force are deemed important. The pH 3 prepared TiO2 DOPC SLBs are destabilized at neutral pH, indicating reversible nature of the interaction. This work has provided new insights into two important materials interacting with common liposomes, which are important for reproducible biosensing, device fabrication, and drug delivery applications.
关键词： coordination chemistry,liposome fusion,SiO2,TiO2,charge,supported lipid bilayers
更新于2025-09-04 15:30:14
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Study on Modification of SiO2 Thin Film Surface Morphology and Its Electrical Performance
摘要： Silicon dioxide thin film was prepared by thermal growth method and PMMA film layer was prepared by spin coating. Silane coupling agent octadecyltrichlorosilane (OTS) be used to modified the surface of SiO2. The result of atomic force microscope (AFM) showed that using PMMA and OTS modified SiO2 layer can effectively improve the surface flatness and reduce the surface energy. The PMMA insulating layer reduces the contact barrier between the organic semiconductor insulating layer and the growth of thin films of copper phthalocyanin became more consistent. Compare with the single SiO2 insulation layer, thin film transistor devices on SiO2/PMMA and SiO2/OTS compound insulation layer with improved carrier mobility and lower threshold voltage. Experimental results showed that using double insulation layer structure can effectively improve the performance of organic thin film transistor.
关键词： SiO2,Insulator,PMMA,Octadecyltrichlorosilane
更新于2025-09-04 15:30:14
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Calcination Effects and Photocatalytic Activity of Porous SiO2-TiO2 Material
摘要： A porous SiO2-TiO2 photocatalyst was prepared through co-sol-gel method using PEG1000 template for photocatalytic degradation of methyl orange. Photocatalytic degradation was conducted after adsorption equilibrium to identify the contribution of both adsorption and photocatalytic degradation. The optimum calcination condition for the porous SiO2-TiO2 is 500 °C for 3 h. The adsorption of methyl orange on the photocatalyst has no apparent change in the whole temperature range. Nearly 96.5 % of the initial methyl orange is removed in 100 min under UV light irradiation with the existence of the porous SiO2-TiO2. Methyl orange degradation follows the first order kinetics equation. The azo and benzene structure are degraded into small molecules during photocatalytic oxidation process.
关键词： Photocatalysis,Composite,SiO2,TiO2
更新于2025-09-04 15:30:14
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Synthesis of TiO2/SiO2-B2O3 Ternary Nanocomposites: Influence of Interfacial Properties on their Photocatalytic Activities with High Resolution Mass Spectrometry Monitoring
摘要： An investigation on unusual interface properties of unprecedented ternary composites, formed by the inclusion of assorted proportions of B2O3 into TiO2/SiO2 structure, is conducted herein. The influences of B2O3 content and calcination temperature were evaluated. The precursor TiO2/SiO2 material was synthesized via a simple sol-gel procedure that was followed by B2O3 inclusion via maceration and calcination. The materials were fully characterized and their photocatalytic performance to degrade the Indigo Carmine dye investigated. The material prepared with a B/Ti molar ratio of 1 and at calcination temperature of 350 °C (B1-350) showed the best performance, with a superior photocatalytic activity than that of commercial TiO2. The presence of B2O3-TiO2-SiO2 interfaces in the structure of such material was of critical importance in producing a material with these attractive features. Finally, high resolution mass spectrometry monitoring allowed for the characterization of the main degradation products formed under these conditions.
关键词： high resolution mass spectrometry,degradation of Indigo Carmine,B2O3-TiO2-SiO2 ternary nanocomposites,photocatalytic activity,by-products characterization,structural defects
更新于2025-09-04 15:30:14
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Effect of Deposition Method on Valence Band Offsets of SiO <sub/>2</sub> and Al <sub/>2</sub> O <sub/>3</sub> on (Al <sub/>0.14</sub> Ga <sub/>0.86</sub> ) <sub/>2</sub> O <sub/>3</sub>
摘要： There are often variations in reported valence band offsets for dielectrics on semiconductors and some of the reasons documented include metal or carbon contamination, interfacial disorder, variations in dielectric composition, thermal conditions, strain, and surface termination effects. In this paper we show that there are differences of up to 1 eV in band alignments for the common gate dielectrics SiO2 and Al2O3 on single crystal (Al0.14Ga0.86)2O3, depending on whether they are deposited by sputtering or Atomic Layer Deposition. In the case of Al2O3, this changed the band alignment from nested (type I) to staggered gap (type II). The valence band offset at each heterointerface was measured using X-Ray Photoelectron Spectroscopy and was determined to be ?0.85 ± 0.15 eV for sputtered Al2O3 and 0.23 ± 0.04 eV for ALD Al2O3 on β-(Al0.14Ga0.86)2O3, while for SiO2 it was 0.6 ± 0.10 eV for sputtered and 1.6 ± 0.25 eV for ALD. These results are consistent with recent results showing that the surface of Ga2O3 and related alloys are susceptible to severe changes during exposure to energetic ion environments.
关键词： Al2O3,(Al0.14Ga0.86)2O3,SiO2,valence band offsets,Atomic Layer Deposition,X-Ray Photoelectron Spectroscopy,sputtering
更新于2025-09-04 15:30:14