Differential Selective Etching of Functional Groups Strategy for Preparation of Organic Hollow Porous Silica

In this study, different structural of organic hollow porous silica were prepared based on differential selective etching of functional groups strategy, using ammonia as catalyst, cetyltrimethylammonium bromide (CTAB) as pore-forming agent and emulsifier, cyano silica (CN-SiO2 ) or vinyl silica (V-SiO2 ) formed by hydrolysis condensation of 2-cyanoethyl triethoxysilane (CTES) or vinyl triethoxysilane (VTES) were used as cores, NH-SiO2 prepared by 3-aminopropyl triethoxysilane (APTES), SH-SiO2 prepared by mercaptopropyl trimethoxysilane (MPTMS) and UD-SiO2 prepared by urea-propyl triethoxysilane (UPTES) as shells, separately. The morphology and structure of the products were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The study results showed that CN-SiO2 as core was considered to be benefit for the preparation of organic hollow porous silica compared to V-SiO2 as core. In addition, core-shell structure obtained from CN-SiO2 NH-SiO2 tend to be changed into hollow porous structure in alkaline condition on account of differential selective etching of functional groups strategy.