The conformation and dynamics study of amphoteric copolymers, P(sodium 2‐methacryloyloxyethanesulfonate‐co‐2‐methacryloyloxyethyltrimethylammonium iodide), using viscometry, 14N‐, and 23Na‐NMR

Solution conformations and dynamic mobilities of novel amphoteric copolymers were studied for aqueous solutions of p(sodium 2‐methacryloxyethanesulfonate‐co‐2‐methacryloy‐loxyethyltrimethylammonium iodide) [P(NaMES‐co‐METMAI)] as a function of com‐position, concentration, and addition of HCI or KCI. As HCI or KCI was added successively to 5 w/v% copolymer solutions, the reduced viscosities of the solutions were reduced except the 1:1 copolymer solution. The dynamic mobility of the cationic side chain was estimated with the quadrupolar 14N‐NMR relaxation technique. The motion of the interacting coun‐terion, Na+, was studied by Poisson‐Boltzmann electrostatic theories and the quadrupolar 23Na‐NMR. Since the intramolecular 1:1 ion pair between MES‐ and METMA+ acts as an effective charge‐screening factor, the copolymers P(NaMES‐co‐METMAI) behave as ordinary polyelectrolytes with the exception of the 1 : 1 copolymer.