A monomer has the structure wherein R is an organic group comprising a polymerizable carbon-carbon double bond or carbon-carbon triple bond; X and Y are independently at each occurrence hydrogen or a non-hydrogen substituent; EWG1 and EWG2 are independently at each occurrence an electron-withdrawing group; p is 0, 1, 2, 3, or 4; n is 1, 2, 3, or 4; and M+ is an organic cation. A polymer prepared from monomer is useful as a component of a photoresist composition.