opolymeric segment consisting essentially of copolymerized free radically copolymerizable monomer, Z is a divalent linking group, G6 represents monovalent moieties which can independently be the same or different selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, fluoroalkyl, hydrogen, and --ZSA; G2 comprises A; G4 comprises A; R1 represents monovalent moieties which c