There is provided a curable composition comprising a fluorinated block copolymer having (a) at least one A block, wherein the A block is a semi-crystalline segment comprising repeating divalent monomeric units derived from at least a fluorinated monomer; and (b) at least one B block, wherein the B block is a segment comprising repeating divalent monomeric units that comprises at least a fluorinated monomer and a nitrile-containing cure-site monomer.