Method of making inorganic porous particles

Abstract

Sol-gel inorganic porous particles are composed of an inorganic compound that provides an inorganic solid phase including an external particle surface. They also have a first set of pores wherein the pores have an average diameter of less than 100 nm and a second set of pores wherein the pores have an average diameter of at least 100 nm, which second set of pores contains stabilizing organic microgel particles. These inorganic porous particles are prepared using a first oil phase comprising a first water-immiscible aprotic solvent having a dielectric constant of less than 10 and having dissolved therein organic microgel particles. An aqueous phase comprising a polar solvent, an inorganic gel precursor, a catalyst, and a dispersing surfactant is neutralized to initiate condensation of the inorganic gel precursor. An oil-in-water emulsion is then formed with the organic microgel particles in the first oil phase, which is dispersed as first oil phase droplets in the aqueous phase. A second oil phase is combined with the oil-in-water emulsion with the second oil phase to form an oil-in-water-in-oil emulsion comprising the first oil phase droplets in the aqueous phase.