THE presence of silica in blood, and the much larger amounts sometimes found in urine, indicate that silica is appreciably soluble in body fluids. The determination of such solubility, however, is a matter of considerable difficulty and different results have been obtained by various workers, owing to the operation of such variable factors as particle size, concentration of suspension, method o...

The aim of this study is to analyze the behaviour of dense colloidal suspensions in flow by acoustic spectroscopy. The destabilization and the aggregation of stable colloidal silica dispersions in a stirred tank are obtained by addition of salt. Experiments were made in order to observe the influence of different operating parameters, like silica concentration, temperature and stirring speed, o...

Spherical silica particles that are able to assemble at a phase boundary of a dual-phase mixture of water and an immiscible organic solvent were prepared by a partial modification of their surface hydroxyl groups with an alkylsilylation agent. Scanning electron microscopic observation of these particles in which their remaining surface hydroxyl groups had been selectively modified with colloida...

Colloidal and sol-gel procedures have been used to prepare heterogeneous catalysts consisting of platinum metal particles with narrow size distributions and well defined shapes dispersed on high-surface-area silica supports. The overall procedure was developed in three stages. First, tetrahedral and cubic colloidal metal particles were prepared in solution by using a procedure derived from that...

The efficient synthesis of all-acrylic, film-forming, core-shell colloidal nanocomposite particles via in situ aqueous emulsion copolymerization of methyl methacrylate with n-butyl acrylate in the presence of a glycerol-functionalized ultrafine silica sol using a cationic azo initiator at 60 °C is reported. It is shown that relatively monodisperse nanocomposite particles can be produced with ty...

colloidal nanosilica is currently being produced by various methods which are mainly high energy intensive and/or not environmentally friendly. it is therefore essential to develop new energy-efficient and environmentally friendly technologies. this paper introduces a new ultrasound assisted route based on alkali leaching of silica fume for synthesis of colloidal silica nanoparticles. the ef...

Fully sulfonated poly(styrenesulfonate) brushes were grown from the surface of colloidal silica particles and used to prepare stable trichloroethylene-in-water and heptane-in-water Pickering emulsions. These particles were highly charged and colloidally stable in water but could not be dispersed in trichloroethylene or heptane. Both two-phase (emulsion plus neat water) and three-phase (emulsion...

A method is presented to tune the holes in colloidal masks used for nanolithography. Using a simple wet-chemical method, a thin layer of silica is grown on masks of silica particles. The size of the holes is controlled by the amount of tetraethoxysilane (TEOS) added. More accurate tuning of the hole size is possible in the presence of a calibrated seed dispersion of silica colloids. We demonstr...