title: Preparation of silica microspheres encapsulating phase-change material by sol-gel method in O/W emulsion.
abstract: 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 - 8 microm) silica microspheres encapsulating n-pentadecane can be successfully created from acidic solutions ([H+] > or = 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.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, ROC.
authors.forename: L Y
authors.initials: LY
authors.lastname: Wang
authors.forename: P S
authors.initials: PS
authors.lastname: Tsai
authors.forename: Y M
authors.initials: YM
authors.lastname: Yang
mesh_terms: D004339:Drug Compounding / Q000379:methods; D004655:Emulsions; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D012822:Silicon Dioxide
chemical_list: D004655:Emulsions; D005782:Gels; D012822:Silicon Dioxide