A copolymer has formula: wherein R1-R5 are independently H, C1-6 alkyl, or C4-6 aryl, R6 is a fluorinated or non-fluorinated C5-30 acid decomposable group; each Ar is a monocyclic, polycyclic, or fused polycyclic C6-20 aryl group; each R7 and R8 is —OR11 or —C(CF3)2OR11 where each R11 is H, a fluorinated or non-fluorinated C5-30 acid decomposable group, or a combination; each R9 is independently F, a C1-10 alkyl, C1-10 fluoroalkyl, C1-10 alkoxy, or a C1-10 fluoroalkoxy group; R10 is a cation-bound C10-40 photoacid generator-containing group, mole fractions a, b, and d are 0 to 0.80, c is 0.01 to 0.80, e is 0 to 0.50 provided where a, b, and d are 0, e is greater than 0, the sum a+b+c+d+e is 1, l and m are integers of 1 to 4, and n is an integer of 0 to 5. A photoresist and coated substrate, each include the copolymer.