Patent ID: 7989512

Claim:
A method of forming an ionomeric membrane comprising a polymer unit having formula 1: wherein: P 1 , P 2 , are each independently absent, —O—, —S—, —SO—, —SO 2 —, —CO—, —NH—, —NR 2 —, or —R 3 —; R 1 is —OR 5 , —NR S , —X, —NHR 5 Z 2 , —OR 5 Z 2 , or —NHSO 2 CF 3 ; R 2 is C 1-25 alkyl or C 1-25 aryl; R 3 is C 1-25 alkylene, C 1-25 perfluoroalkylene, or C 1-25 arylene; R 4 is trifluoromethyl, C 1-25 alkyl, C 1-25 perfluoroalkylene, C 1-25 aryl, or another E 1 group; R 5 is C 1-25 alkyl or C 1-25 aryl; E 1 is an aromatic-containing moiety; Z 2 is —SO 3 H, —PO 3 H, —OH, or —NH 2 ; X is an —OH, a halogen, an ester, or i is an integer from 1 to 10,000; and Q 1 is a fluorinated cyclobutyl moiety, the method comprising: a) reacting a polymer comprising a polymer unit having formula 3 in chlorosulfonic acid to form a first precipitate, the first precipitate comprising a polymer comprising a polymer unit having formula 4 and dissolves in a polar aprotic solvent to form a first solution: b) forming a polymeric membrane from the first solution, the polymeric membrane including the polymer comprising a polymer unit having formula 4; and c) reacting the polymer comprising a polymer unit having formula 4 with a nucleophilic compound to form a base polymer having polymer unit 1.