Dynamics and structure of an amphiphilic triblock copolymer of styrene and 5-(N,N-diethylamino) isoprene in selective solvents

Abstract

Solution properties of a highly asymmetric aminofunctionalized triblock copolymer of 5-(N,N-diethylamino)isoprene and styrene were investigated in dilute regime. Toluene, THF, 1,4-dioxane, or DMF were used to prepare the solutions. It was found that the solvent selectivity for one or both block affects the copolymer solution behavior as reflected by the calculated parameters through light-scattering techniques: weight-averaged, molecular-weight ̄Mw, radius of gyration Rg, translational diffusion coefficient D0, and hydrodynamic radius Rh. According to what was determined, the quality of the polymer-solvent interactions decreases in the order: toluene, THF, 1,4-dioxane, and DMF. After quaternization with dimethyl sulfate, the triblock copolymer consisted of a polystyrene (PS) block with short poly [5-(N,N,N-diethylmethylammonium)isoprene][methyl sulfate] block at both chain ends, shows a better solvation in polar solvents. Transmission electron microscopy (TEM) was used to characterize the crew-cut aggregates prepared from the quaternized copolymer.