Abstract: | Polymers tagged with a local pH reporter were synthesized. A methacrylate-type monomer containing a merocyanine dye residue as a reporter dye—1-(2-methacryloyloxyethyl)-4-(2-(4-hydroxyphenyl)-ethenyl)quinolinium bromide—was synthesized. Its homopolymer and copolymers with sodium 2-acrylamido-2-methylpropanesulfonate were prepared by free radical polymerization. These polymers showed a characteristic color change in aqueous solutions from yellow to red with increasing pH from acidic to basic conditions according to the acid-base equilibria of the merocyanine dye residues. Since the electrostatic potential and polarity of media have a strong effect on the acid–base equilibria, the pendant merocyanine residues are expected to serve as a reporter to provide information on the local environments around the polymer chain at which the dye molecules are incorporated. |