Patent ID: 8173325

Claim:
A method for producing a functional membrane comprising: a step of ion irradiation, in which a polymer film substrate containing nonconductive inorganic particles is irradiated with high-energy heavy ions to the extent of 10 4 /cm 2 to 10 14 /cm 2 such that active species are generated in the film substrate; and a step of graft polymerization subsequent to the ion irradiation step, in which one or more monomers selected from group A are added such that the monomers are graft polymerized with the film substrate; wherein group A consists of: (1) the group of monomers consisting of CF 2 ═CF(SO 2 X 1 ) where X 1 denotes a halogen group represented as —F or —Cl , CH 2 ═CF(SO 2 X 1 ), and CF 2 ═CF(OCH 2 (CF 2 ) m SO 2 X 1 ) where m denotes an integer from 1 to 4; (2) the group of monomers consisting of CF 2 ═CF(SO 3 R 1 ) where R 1 denotes an alkyl group represented as —CH 3 , —C 2 H 5 , or —C(CH 3 ) 3 , CH 2 ═CF(SO 3 R 1 ), and CF 2 ═CF(OCH 2 (CF 2 ) m SO 3 R 1 ); (3) the group of monomers consisting of CF 2 ═CF(O(CH 2 ) m X 2 ) where x 2 denotes a halogen group such as —Br or —Cl, and CF 2 ═CF(OCH 2 (CF 2 ) m X 2 ); (4) the group of monomers consisting of CF 2 ═CR 2 (COOR 3 ) where R 2 denotes —CH 3 or —F and R 3 denotes —H, —CH 3 , —C 2 H 5 , or —C(CH 3 ) 3 , and CH 2 ═CR 2 (COOR 3 ); (5) the group of monomers consisting of styrene, 2,4-dimethylstyrene, vinyltoluene, and 4-tert-butylstyrene; and (6) the group of monomers consisting of acenaphtylene, vinylketone represented as CH 2 ═CH(COR 4 ) where R 4 denotes —CH 3 , —C 2 H 5 , or a phenyl group (—C 6 H 5 ), and vinyl ether represented as CH 2 ═CH(OR 5 ) where R 5 denotes —C n H 2n+1 (n=1-5), —CH(CH 3 ) 2 , —C(CH 3 ) 3 , or a phenyl group.