Hydrophilically modified fluorinated membrane (IV)
Disclosed are copolymers which are useful in hydrophilically modifying fluoropolymer membranes. An example of the copolymers is: Also disclosed are a method of preparing such copolymers, a method of modifying fluoropolymer membrane surfaces, and hydrophilic fluoropolymer porous membranes prepared from the copolymers.
1. A composite hydrophilic porous membrane comprising a porous fluoropolymer support and a coating comprising a copolymer, wherein the copolymer comprises repeat units A and B, wherein A is of the formula:
and B is of the formula
wherein:
the copolymer is a block copolymer or a random copolymer;
m and n, the number of repeat units A and B present in the copolymer, range from 1 to about 1000, provided the sum of n and m is equal to or greater than 10,
wherein the copolymer is optionally crosslinked.
2. The composite hydrophilic porous membrane of claim 1 , wherein the copolymer has chain end groups selected from aryl groups and alkoxy groups.
3. The composite hydrophilic porous membrane of claim 1 , wherein the copolymer is of one of the following formulae:
4. The composite hydrophilic porous membrane of claim 3 , wherein the copolymer is of one of the following formulae:
5. The composite hydrophilic porous membrane of claim 3 , wherein the copolymer is of one of the following formulae:
6. A method of hydrophilically modifying a porous fluoropolymer support comprising:
(i) providing a porous fluoropolymer support;
(ii) coating the porous fluoropolymer support with a solution comprising a solvent and a copolymer, wherein the copolymer comprises repeat units A and B, wherein A is of the formula:
and B is of the formula
wherein:
the copolymer is a block copolymer or a random copolymer;
m and n, the number of repeat units A and B present in the copolymer, range from 1 to about 1000, provided the sum of n and m is equal to or greater than 10;
(iii) drying the coated support from (ii) to remove at least some of the solvent from the solution comprising said copolymer; and optionally
(iv) crosslinking said copolymer present in the coated support.
7. The method of claim 6 , wherein the copolymer has chain end groups selected from aryl groups and alkoxy groups.
8. The method of claim 6 , wherein the copolymer is of one of the following formulae:
9. A hydrophilically modified porous fluoropolymer membrane produced by the method of claim 6 .
10. The composite hydrophilic porous membrane of claim 1 , wherein the porous fluoropolymer support is selected from PTFE, PVDF, PVF (polyvinyl fluoride), PCTFE (polychlorotrifluoroethylene), FEP (fluorinated ethylene-propylene), ETFE (polyethylenetetrafluoroethylene), ECTFE (poly ethylenechlorotrifluoroethylene), PFPE (perfluoropolyether), PFSA (perfluorosulfonic acid), and perfluoropolyoxetane.
11. The composite hydrophilic porous membrane of claim 1 , which is configured in a planar, flat sheet, pleated, tubular, spiral, or hollow fiber configuration.