Structural and dynamic characteristics of thermo- and pH-sensitive copolymers of 2-(diethylamino)ethyl methacrylate and 2-deoxy-2-methacrylamido-d-glucose

Abstract Polarized luminescence and flow birefringence methods were used in the studies of structural and dynamic characteristics of 2-(diethylamino)ethyl methacrylate and 2-deoxy-2-methacrylamido- d -glucose copolymers with varied content of cationic monomer units while changing temperature, pH and ionic strength of solutions. It was demonstrated that with increasing temperature, nanosecond relaxation times τ IMM (which characterize intramolecular mobility of fragments of copolymer chain in solution) increase over a relatively narrow temperature range. Increase in relaxation times indicates strengthening intramolecular interactions and the formation of intramolecular hydrophobic domains. From the obtained flow birefringence data, it follows that in the vicinity of the lower critical solution temperature (LCST) we have molecular dispersed diluted copolymer solutions. The influence of temperature and ionic strength of solutions on the transition temperature were also studied. The observed changes in intramolecular interactions are accompanied by insignificant changes in root-mean-square dimensions of macromolecular coils; however, coils retain their asymmetry.