| 摘要 |
The invention provides a process for making an inorganic hollow particle dispersion through an interfacial miniemulsion sol-gel reaction comprising: providing a mixture of an oil phase comprising at least one non-reactive solvent and at least one solvent-based silica precursor, and a water phase comprising water and at least one surfactant; forming an oil-in-water emulsion by high energy shearing the mixture from step (a) at an energy density of at least about 10^6 J/m^3, in the absence of a catalyst or alcohol cosolvent, to form thin shell hollow silica templates, and wherein the concentration of solvent-based silica precursor is about 0.01 to about 5 wt %, the silica precursor to non-reactive solvent ratio is about 0.002 to about 3, oil to water ratio is about 0.01 to about 0.4, and surfactant concentration is about 0.001 wt % to about 5 wt %; initiating a one-step sol-gel reaction to form thin shell silica hollow particles; adjusting the pH of the emulsion to above about 8, by typically adding base; adding at least one water based silica precursor solution to emulsion at constant feeding rate over at least about 1 hour while maintaining the pH of the solution at about 8 by simultaneously continuously adding acid, or adding all water based silica precursor solution at once and then slowly lowering the pH to about 8 by continuously adding acid over at least about one hour, wherein the concentration of water based silica precursor is about 0.5 wt% to about 15 wt%, more typically about 1 wt% to about 10 wt%, based on the total weight of the dispersion; and holding the solution for about 0.5 to about 16 hours, at room temperature, more typically at about 20 °C to about 95 °C, and still more typically at about 20 °C to about 70 °C, with optional stirring, to allow the silica precursor to hydrolyze and condense to form a layer or coating of silica on the thin shell hollow silica templates, resulting in a hollow silica particle having a particle size of less than about 400 nm. |
