A compound has formula (I): Q-O-(A)-Z−G+  (I) wherein Q is a halogenated or non-halogenated, C2-30 olefin-containing group, A is a fluorine-substituted C1-30 alkylene group, a fluorine-substituted C3-30 cycloalkylene group, a fluorine-substituted C6-30 arylene group, or a fluorine-substituted C7-30 alkylene-arylene group, Z is an anionic group comprising sulfonate, sulfonamide, or sulfonimide, and G+ has formula (II): wherein X is S or I, each R0 is halogenated or non-halogenated and is independently C1-30 alkyl group; a polycyclic or monocyclic C3-30 cycloalkyl group; a polycyclic or monocyclic C4-30 aryl group; or a combination of these, wherein when X is S, one of the R0 groups is optionally attached to one adjacent R0 group by a single bond, and a is 2 or 3, wherein when X is I, a is 2, or when X is S, a is 3. A copolymer, a photoresist, a coated substrate and method of patterning are disclosed.