Preparation of silica microspheres encapsulating phase-change material by sol-gel method in O/W emulsion

摘要

Spherical silica microcapsules containing phase-change material (PCM)were prepared by the sol-gel method in O/W emulsion.This is the first time that inorganic encapsulation of PCM with core/shell structure has been studied.The results of this synthesis revealed that micron size (4 approx 8 mu m)silica microspheres encapsulating n-pentadecane can be successfully created from acidic solutions ([H~+]>=1.44 N)by using cationic surfactants as the emulsifiers.The identification of the mechanisms for the formation of silica shell at the oil-water interface indicates that it should be the charge-controlled mechanism through S~+X~-I~+(positively charged surfactant-halide ion-positively charged silica species)electrostatic interactions or the reaction rates-controlled mechanism working on cationic emulsifiers.