Poly (acryloxyethyl-trimethylammonium chloride-co-2-hydroxyethyl methacrylate)[poly (Q-co-H)] was prepared by free radical polymerization in aqueous solution at 608C using potassium persulfate as initiator. Spectroscopic characterization confirmed the formation of poly (Q-co-H) and the molar fractions of acryloxyethyl-trimethylammonium chloride monomer units incorporated in the copolymers were determined by potenciometric titrations. The monomer reactivity ratios for Q and H are found to be rQ 5 0.04 6 0.01 and rH 5 3.22 6 0.84 using Fineman–Röss method and rQ 5 0.06 and rH 5 3.61 using Genetic Algorithms method. Finally we studied reaction between poly (Q-co-H) and sodium alginate by conductimetric measurement. Ó 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 1680–1688, 2008