Permeation properties of microporous membranes prepared via coating of evaporated polydimethylsilane

A microporous membrane has been prepared by coating alumina support with evaporated polydimethylsilane, followed by curing and pyrolysis. Permeation properties of the membrane exhibit gas separation capability. At permeation temperature 180 °C, helium permeance is 1.1×10−9, nitrogen 1.5×10−10, and iso-butane 3.7×10−11 mol s−1 Pa−1 m−2. The membrane permeance is enhanced when the pyrolysis is carried out in the presence of low-pressure steam, and its percentage increase rises with the pyrolysis temperature. But the membrane selectivities of permanent gas pairs are damaged.