SiO_2-TiO_2复合膜的制备及表征

Preparation and Characterization of SiO_2-TiO_2 Composite Membranes

以正硅酸乙酯和钛酸丁酯为原料,用溶胶-凝胶法制备SiO2-TiO2复合膜。采用TG-DTG、FT-IR和AFM等测试技术对膜的热稳定性、凝胶膜热处理前后的结构变化和复合膜的表面微观形貌进行表征。实验结果表明:分级干燥或者保持65%相对湿度的直接干燥可以得到无裂纹的凝胶膜;复合膜的热稳定较好,650℃以后没有明显的质量损失;焙烧过程中,不同升温区间采用不同的升温速率,以防止膜开裂;复合膜在制备过程中形成了Si-O-Ti键,经烧结后Si-O-Ti键位置没有发生明显位移;原子力显微镜分析表明,膜表面完整无缺陷,薄膜平均孔径约为50nm。

SiO2-TiO2 composite membranes were prepared by sol-gel process using tetraethoxy silicone（TEOS） and tetrabutyl titivate（TBOT） as raw materials.Thermal stability,structural transformation before and after heat treatment,surface morphologies of composite membranes were characterized by means of thermogravimetry-derivative thermogravimetry（TG-DTG）,Fourier transform infrared（FT-IR） spectroscopy and atomic force microscopy（AFM） etc.The results show that gradual drying or directly drying under relative humidity 65% can get gel membranes without cracks;composite membrane＇s thermal stability is good,there is no significant mass loss after being heat treated at 650℃;In the process of sintering,different heating rates are set in different temperature ranges in order to prevent membranes cracking;Si-O-Ti bond forms during the preparation process,and the position doesn＇t displace obviously after being sintered.Atomic force microscopy analysis shows that membrane surfaces are integrit,and membrane pore size is about 50nm.