摘要 |
A differential pore-collapsed separation membrane particularly useful as a gas-separation membrane and a method of preparing such differential pore-collapsed membrane, which method comprises treating an asymmetric membrane, while under one-sided constraint, with a treating solution comprising a volatile nonsolvent and a swelling agent and/or a solvent, and drying the treated membrane, to provide for the controlled, differential pore collapse of the small pores of the top skin of the membrane to a smaller pore-size distribution in the membrane generally less than about 10 Angstroms.
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