Formation of Chemically Modified Ceramic Membranes and TheirTransport Characterization

本课题研究化学气相沉积技术改性陶瓷膜。美国铝业公司的氧化铝前驱体材料是不对称的，具有α -氧化铝支撑和5 b> m的γ -氧化铝表皮层。它们的最小孔径（40 >）使它们不适合小分子的精细分子筛选分离。使用一系列氟化硅烷来精确控制皮肤层狭缝状孔的尺寸减小。在精心设计的实验中，对孔隙修饰过程发生的机制及其可重复性进行了测试。研究的重点是这些模型材料的基本输运性质的测量和建模。这些材料的详细形态由气体和液体系统探测。这些数据提供了新的见解，并允许测试理论来分析孔径接近分子尺寸的介质中的输运现象。这种新型陶瓷膜将在气体混合物的分离中找到新的应用。

This project studies ceramic membranes modified by a chemical vapor deposition technique. The alumina precursor materials from Alcoa are asymmetric, with an alpha-alumina support and a 5 >m gamma-alumina skin layer. Their minimum pore dimension (40 >) makes them inappropriate for fine molecular-sieving separations of small molecules. A series of fluorinated silanes are used to provide precisely controlled decreases in the sizes of the slit-shaped pores of the skin layer. The proposed mechanism by which the pore modification process occurs and its reproducibilty are tested in carefully designed experiments. Studies are focused on the measurement and modeling of the fundamental transport properties of these model materials. The detailed morphology of these materials are probed by gaseous and liquid systems. The data provide new insights and allow testing theories for analyzing transport phenomena in media with pore sizes approaching molecular dimensions. The new ceramic membranes should find new applications in separations of gaseous mixtures.