Method for the preparation of ionomer films

A method for forming a perfluorosulfonate ionmer film comprising:

• (a) forming a solution of a perfluorosulfonate inomer in its salt form:
• (b) coating a substrate with the perfluorosulfonate ionomer solution;
• and
• (c) heating the coated substrate to a temperature of at least about 20.degree. C. for sufficient time to deposit a solvent-resistant film of a perfluorosulfonate ionomer onto the substrate.
• wherein the perfluorosulfonate ionomer is a copolymer of a first repeating unit selected from a first group of monomers, a second repeating unit selected from a second group of monomers, and a third repeating unit selected from a third group of monomers;
• wherein the first group of monomers is represented by the general formula:
• CF.sub.2 .dbd.CZZ'
• where:
• Z and Z' are independently selected from the group consisting of --H, --Cl, --F, or --CF.sub.3 ;
• and
• the second group of monomers is represented by the general formula:
• Y--(CF.sub.2).sub.a --(CFR.sub.f).sub.b --(CFR.sub.f').sub.c --O--[CF(CF.sub.2 X)--CF.sub.2 --O].sub.n --CF.dbd.CF.sub.2
• where:
• Y is selected from the group consisting of --SO.sup.2 OA;
• A is --H+, an alkali metal, or --R.sub.1 R.sub.2 R.sub.3 R.sub.4 N+;
• R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are independently selected from the group consisting of --H+, a branched or linear alkyl radical having from 1 to about 10 carbon atoms or an aryl radical;
• a is 0-6;
• b is 0-6;
• c is 0 or 1;
• provided a+b+c is not equal to 0;
• X is --Cl, --Br, --F, or mixtures thereof when n>1;
• n is 0 to 6;
• and
• R.sub.f and R.sub.f' are independently selected from the group consisting of --F, --Cl, perfluoroalkyl radicals having from 1 to about 10 carbon atoms and fluorochloroalkyl radicals having from 1 to about 10 carbon atoms and
• the third group of monomers is represented by the general formula:
• Y'--(CF.sub.2).sub.a' --(CFR.sub.f).sub.b' --(CFR.sub.f').sub.c' --O--[CF (CF.sub.2 X')--CF.sub.2 O].sub.n' --CF.dbd.CF.sub.2
• where:
• Y' is --F, --CI or --Br;
• a' and b' are independently 0-3;
• c is 0 or 1;
• provided a'+b'+c' is not equal to 0;
• n' is 0-6;
• R.sub.f and R.sub.f' are independently selected from the group consisting of --Br, --C;, --F, perfluoroalkyl radicals having from about 1 to about 10 carbon atoms, and chloroperfluoroalkyl radicals having from 1 to about 10 carbon atoms;
• and
• X' is --F, --Cl, --Br, or mixtures thereof when n'>1.

A method for forming a perfluorosulfonate ionomer film comprising:

• (a) forming a solution of a perfluorosulfonate ionomer in its salt form;
• (b) coating a substrate with the perfluorosulfonate ionomer solution;
• and
• (e) heating the coated substrate to a temperature of at least about 120.degree. C. for sufficient time to deposite a solvent-resistant film of a perfluorosulfonate ionomer onto the substrate
• wherein the perfluorosulfonate ionomer is a copolymer of a first repeating unit selected from a first group of monomers and a second repeating unit selected from a second group of monomers wherein the first group of monomers is represented by the general formula:
• CF.sub.2 .dbd.CZZ'
• where:
• Z and Z' are independently selected from the group consisting of --H, --Cl, --F, or --CF.sub.3 ;
• and
• the second group of monomers is represented by the general formula:
• Y--(CF.sub.2).sub.a --(CFR.sub.f).sub.b --(CFR.sub.f').sub.c --O--CF(CF.sub.2 X)--[CF.sub.2 --O].sub.n --CF.dbd.CF.sub.2
• where:
• Y is selected from the group consisting of --SO.sub.2 OA;
• A is --H+, an alkali metal, or --R.sub.1 R.sub.2 R.sub.3 R.sub.4 N+;
• R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are independently selected from the group consisting of --H+, a branched or linear alkyl radical having from 1 to about 10 carbon atoms or an aryl radical;
• a is 0-6;
• b is 0-6;
• c is 0 or 1;
• provided a+b+c is equal to 2 or 3;
• X is --Cl, or --F;
• n is 0 or 1;
• and
• R.sub.f and R.sub.f' are --F.

A method for forming a perfluorsulfonate ionomer film comprising:

• (a) forming a solution of a perfluorosulfonate ionomer in its salt form;
• (b) coating a substrate with the perfluorosulfonate ionomer solution;
• and
• (c) heating the coated substrate to a temperature of at least about 120.degree. C. for sufficient time to deposite a solvent-resistant film of a perfluorosulfonate ionomer onto the substrate
• wherein the solvent is selected form the group of solvents consisting of N,N'-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methyl pyrrolidone, triphenylphosphate, tetramethyl urea, dimethylacetamide, sulfolane, butyrolactone and ethylene glycol and
• wherein water is present in the solvent to enhance dissolution of the polymer.