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,600℃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,干燥和烧结时,体系内的有机物和水分挥发,在体系内造成了丰富的孔道结构,薄膜平均孔径约为50 nm。

SiO2-TiO2 composite membrane was prepared by sol-gel process using tetraethoxy silicone （TEOS） and tetrabutyl titivate （TBOT） as raw materials. The thermal stability, the structural transformation before and after heat treatment, the surface morphology of composite membrane were characterized by TG-DTG, FI-IR and AFM, etc. The results showed that gradual drying or directly drying keeping 65% relative humidity can get gel film without crack; the composite membrane＇s thermal stability was good, there was no significant quality loss after 600℃; in the process of sintering, the different temperature range should use different heating rates, in order to prevent membrane cracking; during the preparation process, Si-O-Ti bond formed, and the position didn＇t move obviously. Atomic force microscopy analysis showed that the membrane surface was in its integrity with no defects, the volatilization of the organic compounds and water within the system formed a rich pore structure, and the membrane pore size was about 50 nm.