نتایج جستجو برای: stöber method
تعداد نتایج: 1630130 فیلتر نتایج به سال:
for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...
New bio-materials have recently gained interest for use in insulation panels in walls, but wider adoption by the building industry is hindered by their intrinsic properties. The fact that such materials are mainly composed of cellulose makes them combustible, and their hydrophilic surface presents a high water uptake, which would lead to faster biodegradation. A hydrophobic treatment with silic...
background: multifunctional core-shell magnetic nanocomposite particles with tunable characteristics have been paid much attention for biomedical applications in recent years. a rational design and suitable preparation method must be employed to be able to exploit attractive properties of magnetic nanocomposite particles.objectives: herein, we report on a simple approach for the synthesis of ma...
Spherical silica particles with bifunctional (≡Si(CH2)3NH2/≡SiCH3, ≡Si(CH2)3NH2/≡Si(CH2)2(CF2)5CF3) surface layers were produced by a one-step approach using a modified Stöber method in three-component alkoxysilane systems, resulting in greatly increased contents of functional components. The content of functional groups and thermal stability of the surface layers were analyzed by diffuse refle...
This work describes the synthesis and applications of amphiphilic polystyrene-block-poly(N-vinyl-2-pyrrolidone) (PS-b-PVP) copolymers as a silver and silica nanoparticle surface modification agent. The synthesis of PS-b-PVP was carried out using controlled/living radical polymerization techniques. The synthesis of the block copolymers was confirmed by gel permeation chromatography and hydrogen ...
In this research, submicronsized silica (SiO2) spheres with uniform spherical morphology are grown using the Stöber sol-gel process and subsequently, functionalized with (3-aminopropyl)-trimethoxysilane (APS). These spheres are further modified by chemical binding with L-cysteine (SiO2-CYS). The composition, structure, morphology and surface properties of the particles obtained are characterize...
The work presented investigates how to produce structural colours on textile materials by applying a surface coating of silica nanoparticles (SNPs). Uniform SNPs with particle diameters in a controlled micron size range (207-350 nm) were synthesized using a Stöber-based solvent varying (SV) method which has been reported previously. Photonic crystals (PCs) were formed on the surface of a piece ...
The porous fluorescent SiO2 nanoparticles encapsulating photosensitizer Ru(bpy)3Cl2 were prepared by Stöber method and used as a carrier to immobilize glucose oxidase (GOD) to form the bifunctional porous SiO2 complex nanoparticles (BPSCNp) with the properties of enzymatic catalysis and optical oxygen sensing. The optimal immobilization conditions are as follows: hexadecyltrimethyl ammonium bro...
A new, simple, and "green" method was developed for the surface modification of 20 nm diameter Stöber silica particles with 3-aminopropyl(diethoxy)methylsilane in ethanol. The bulk polycondensation of the reagent was inhibited and the stability of the sol preserved by adding a small amount of glacial acetic acid after appropriate reaction time. Centrifugation, ultrafiltration, and dialysis were...
Silica-based materials with favourable biocompatibility are generally considered as excellent candidates for applications in biomedical fields. However, previous researches mainly focused on the safety of silica-based materials, their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) still need further investigations. In this study, core-shell fluorescent silica nano...
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