PROCESS FOR PREPARING INORGANIC HOLLOW PARTICLE DISPERSIONS USING AN INTERFACIAL MINIEMULSION SOL-GEL REACTION AND A WATER-BASED PRECURSOR

摘要

The disclosure provides a process for making an inorganic hollow particle dispersion using water based precursors through an interfacial miniemulsion sol-gel reaction comprising: a) forming an oil-in-water or water-in-oil minemulsion by high energy shearing water, at least one non-reactive solvent; and at least one surfactant; at an energy density of at least 10^6 J/m^3; wherein the oil to water or water to oil ratio is about 0.01 to about 0.55; and surfactant concentration is about 0.001 wt % to about 5 wt %, based on the total weight of the dispersion; b) adjusting the pH of the emulsion; c) feeding at least one water based silica precursor solution to emulsion at constant feeding rate over several hours wherein the concentration of silica precursor is about 0.005 wt% to about 5 wt%, based on the total weight of the dispersion; while maintaining the pH of the solution at above about 6 or below about 2; d) holding solution at room temperature, with optional stirring to allow the silica precursor to diffuse to the oil/water interface; and e) initiating a one-step sol-gel reaction by adjusting the pH to about 4 to about 10, whereby the water based silica precursor hydrolyzes and condenses to form a silica shell at the oil/water interface resulting in silica hollow particles having a particle size of less than about 400 nm.