Functional fluoropolymers

A fluorinated copolymer comprising copolymerized monomers wherein the monomers consist of vinylidene fluoride and one or more hydrophilic monomers wherein the hydrophilic monomer comprises vinyl alkyl acids, wherein said hydrophilic monomer has the formula (M1):

• wherein R1, R2, and R3 is a hydrogen or a halogen;
• wherein R4 is a C8 linear or branched alkyl group, and
• wherein R5 is carboxylic acid (C(O)OH), alkali metal carboxylate salt (COO−M+), ammonium carboxylate salt (COO−NH4+), alkylammonium carboxylate salt (COO−N(Alk)4+), sulfonic acid (S(O)(O)OH), alkali metal sulfonate salt (S(O)(O)O−M+), ammonium sulfonate salt (S(O)(O)O−NH4+), alkylammonium sulfonate salt (S(O)(O)O−N(Alk)4+), wherein M+is an alkali metal and Alk means alkyl group,
• and wherein the fluorinated copolymer comprises from 90 to 99.99 wt % of polymerized vinylidene fluoride monomer units.