A copolymer comprising monomers copolymerized in the following percentages by weight: (a) from about 40% to about 75% of a monomer of formula I: R.sub.f --CH.sub.2 CH.sub.2 --OC(O)--C(R).dbd.CH.sub.2 I (b) from about 15% to about 55% of a monomer of formula II: R.sub.2 --OC(O)--C(R).dbd.CH.sub.2 II (c) from 1.5% to about 5% of a monomer of the formula III: HO--CH.sub.2 CH.sub.2 --OC(O)--C(R).dbd.CH.sub.2 III (d) from 1.5% to about 5% of a monomer of the formula IV: H--(OCH.sub.2 CH.sub.2).sub.m --O--C(O)--C(R).dbd.CH.sub.2 IV (e) from 1% to about 3% of a monomer of the formula V: HO--CH.sub.2 --NH--C(O)--C(R).dbd.CH.sub.2 V (f) from 0% to about to about 9.8% of vinylidene chloride, vinyl acetate, or a mixture thereof (g) from 0% to about 2% of a blocked isocyanate, wherein R.sub.f is a straight or branched-chain perfluoroalkyl group of from 2 to about 20 carbon atoms, each R is independently H or CH.sub.3 ; R.sub.2 is an alkyl chain from 2 to about 18 carbon atoms; and m is 2 to about 10, is disclosed.