Patent ID: 8431645

Claim:
A gradient copolymer composition, comprising a gradient copolymer comprising: repeat units resulting from the polymerization of at least one first monomer M 1 , the corresponding homopolymer of which exhibits a glass transition temperature Tg 1 of less than 20° C., said repeat units representing from 15 to 40% by weight, with respect to the total weight of the copolymer; repeat units resulting from the polymerization of at least one second monomer M 2 , the corresponding homopolymer of which exhibits a glass transition temperature Tg 2 of greater than 20° C., said repeat units representing from 45 to 65% by weight, with respect to the total weight of the copolymer; hydrophilic repeat units resulting from the polymerization of at least one third monomer M 3 , said repeat units representing from 10 to 25% by weight, with respect to the total weight of the copolymer.