Ultrathin polyether sulfone films and their preparation
AssigneeHoechst Celanese Corporation
InventorRachel S. Kohn
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Abstract
Disclosed herein are free-standing, pinhole-free, ultrathin polyether sulfone films having thicknesses of about 400 angstroms or less and a process for preparing them. The films find particular utility in separatory applications.
Claims17
A polyether sulfone free-standing polymer film containing no macroscopic holes and having a thickness of about 180 angstroms or less and randomly oriented molecules.
A polyether sulfone film containing no macroscopic holes and having a thickness of about 400 angstroms or less and randomly oriented molecules prepared according to the process comprising:
- (a) preparing a casting solution containing a polyether sulfone polymer at about the two to about the twelve percent by weight level, based on the total weight of the casting solution, in 1,2,3-trichloropropane or 1,1,2,2-tetrachloroethane;
- (b) depositing the casting solution on water to form a free-standing film;
- and
- (c) removing the film from the water.
A polyether sulfone film containing no macroscopic holes and having a thickness of about 400 angstroms or less and randomly oriented molecules prepared according to the process comprising:
- (a) preparing a casting solution containing a polyether sulfone polymer having the repeating formula:
- ##STR10## present at about the two or about the twelve percent by weight level, based upon the total weight of the casting solution, in 1,2,3-trichloropropane or 1,1,2,2-tetrachloroethane;
- (b) depositing the casting solution on water to form a free-standing film;
- and
- (c) removing the film from the water.
Dependencies are inferred from the claim text.