疏水介孔二氧化硅膜的制备与表征

Preparation and Characterizaion of Hydrophobic Mesoporous Silica Membranes

用甲基三乙氧基硅烷(MTES)代替部分正硅酸乙酯(TEOS)作为前驱体,以聚乙烯醚-聚丙烯醚-聚乙烯醚三嵌段共聚物(P123)作有机模板剂,通过共水解缩聚反应制备了甲基修饰的介孔SiO2膜。利用N2吸附、FTIR、29SiMASNMR以及接触角测量仪对膜的孔结构和疏水性进行了表征。结果表明,修饰后的膜材料具有良好的介孔结构,最可几孔径为4.65nm,孔体积为0.69cm3·g-1,比表面积为938.4m2·g-1;同时疏水性明显提高,当nMTES/nTEOS达到1.0时,其对水的接触角达到109°±1.1°。气体渗透实验表明气体通过膜孔的扩散由努森机制所控制。

Methyl-modified mesoporous silica membranes were prepared by acid catalyzed co-hydrolysis and condensation reaction of tetraethylorthosilicate （TEOS） and methyhriethoxysilane （MTES） in the presence of triblock copolymer poly （ethylene glycol）-B-poly （propylene glycol）-B-poly （ethylene glycol） （P123） in ethanol. The pore structure and hydrophobic property of the final materials were characterized by Nitrogen adsorption, FTIR, ^29Si MAS NMR and contact angle meter. The results show that modified silica membranes have a desirable pore structure, with a pore size of 4.65 nm, a pore volume of 0.69 cm^3·g^-1 and a BET surface area of 938.4 m^2·g^-1, and tend to be hydrophobic with a water contact angle of 109° ＋ 1.1°as the molar ratio of MTES/TEOS increases to 1.0. Gas permeability test suggests that the gas transport into the membranes is governed by Knudsen diffusion mechanism.