Patent ID: 8808868

Claim:
A copolymer comprising formula (I) wherein R f is C 4 to C 6 fluoroalkyl, optionally interrupted by one or more —O —, —CH 2 —, —CFH—, or combinations thereof; n is an integer from 1 to 10; R 1 and R 2 are each independently H or CH 3 ; R 3 is H, CH 3 , or CH 2 CH 3 ; R 4 is H, CH 3 , or CH 2 CH 3 ; R 5 is C 6 to C 18 alkyl or Y; R 6 is H, CH 3 , or CH 2 CH 3 ; R 7 is H, CH 3 , or CH 2 CH 3 ; R 8 is H, CH 3 , CH 2 CH 3 , or Y; wherein a, b, and c are defined such that either a is 30 to 50 mol %, b is 1 to 10 mol %, and c is 45 to 65 mol %; or a is 35 to 45 mol %, b is 0 mol %, and c is 55 to 65 mol %; provided that (a+b+c) equals 100; Y is R 9 is each independently alkyl, alkyl alcohol, or hydrogen; and m is 1 to 10.