Dispersion Of SiO2 Nanoparticles Research Articles

Investigation into the performance and mechanism of SiO2 nanoparticles and starch composite films

Nanomaterials are often introduced to improve the properties of polymers. In this article, the effects of SiO2 nanoparticles with lager specific areas and special microstructural characters on the properties of starch films were investigated. Firstly, the ultrasonic mixing was used to disperse the SiO2 nanoparticles under different dispersion times, and then the dispersed SiO2 nanoparticles with various ratios were added into starch size. The effects of the dispersion time and the SiO2 content on the mechanical properties of the SiO2/starch composite size were analysed. It was found that the dispersion time and the SiO2 content had significant effects on the tensile and abrasion behaviour of the nanocomposite films. The mechanism of the enhanced mechanical properties of the composite films was examined by analysing the size of the dispersed SiO2 nanoparticles in the dispersion, the surface characters of the films and the structures of the fractured surfaces. And the morphology of the abraded surface was analysed by atomic force microscopy, scanning electron microscope and video zoom microscope.

Electrochemical preparation of TiO2/SiO2 composite film and its high activity toward the photoelectrocatalytic degradation of methyl orange

Uniform TiO2/SiO2 composite films were prepared on ITO substrates by electrodeposition, and highly photoelectrocatalytic (PEC) activity of the composite films was observed toward the degradation of methyl orange (MO) in aqueous solutions. It was further found that their PEC activity was dependent on the electrodeposition parameters including deposition time, solution pH and SiO2 content. Under the optimized condition, the PEC degradation of MO on TiO2/SiO2 composite film electrode could be enhanced about 14 times relative to that on neat TiO2 film electrode. The high PEC activity of the TiO2/SiO2 composite film electrode was mainly attributed to the enhancement of the charge separation of photo-generated electron-hole pairs by the dispersion of SiO2 nanoparticles in the TiO2 matrix with the aid of the applied electric field.

Adsorption and Structural Arrangement of Cetyltrimethylammonium Cations at the Silica Nanoparticle−Water Interface

Although the sorption of cetyltrimethylammonium ion (CTA+) on silica (SiO2) surfaces has been studied extensively, little is known about the interactions between large surfactant molecules and nanosized colloidal particles with a high specific surface area. The aim of the study was to understand the effects of structural arrangements of sorbed CTA+ ions on the stability and surface properties of SiO2 nanoparticles. The extent of the effect of CTA+ sorption on the aggregation behavior of the SiO2 nanoparticle suspension was investigated with the dynamic light scattering (DLS) technique. Both the Fourier transform infrared (FTIR) and Raman spectroscopic techniques were used to probe the sorbed layers of CTA+ on silica surfaces. Results indicate that, at a low surface coverage (less than a monolayer), CTA+ molecules were strongly bound to the SiO2 surface via their trimethylammonium headgroups. A bilayer sorption of CTA+ was observed at a high surface coverage, and the sorption is attributed to the hydrophobic interactions between aliphatic tails of CTA+. Sorption of CTA+ at a low surface coverage also caused the destabilization of the SiO2 nanoparticle dispersion as a result of surface charge neutralization, but redispersion and surface charge reversal of SiO2 colloids occurred at a high surface coverage. The present study thus confirms the adsorption mechanism of the reverse orientation model and contributes to a better understanding of the sorption and structural arrangements of sorbed surfactants at the SiO2 nanoparticle−water interface.