Synthesis of poly(styrene‐co‐allylamine)‐b‐poly(2‐(dimethylamino)ethyl methacrylate) graft copolymers via “grafting from” atom transfer radical polymerization and their self‐assembly in aqueous media

Abstract

AbstractIn this work, we report a new synthetic scheme for synthesis of graft copolymers. At first, poly(styrene‐co‐acrylonitrile) copolymers with different molecular weights were synthesized via atom transfer radical polymerization (ATRP). Then, lithium aluminum hydride was used as reducing catalyst of nitrile groups to obtain poly(styrene‐co‐allylamine) copolymers. Amine groups of poly(styrene‐co‐allylamine) copolymers were reacted to 2‐bromo‐2‐methylpropionyl bromide (BiBB) to yield poly(styrene‐co‐N‐allyl‐2‐bromo‐2‐methylpropanamide) (poly(styrene‐co‐NABMPA)) as macroinitiator for “grafting from” ATRP. Then, ATRP of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) was performed to graft PDMAEMA side chains. Finally, self‐assembly behavior of synthesized graft copolymers was investigated in aqueous media with different pH values and morphology of obtained supramolecular structures was studied. Synthesized copolymers were well‐characterized by 1H NMR, 13C NMR, and gel permeation chromatography. Also, morphology of self‐assembled structures was studied by FE‐SEM images whereas dynamic light scattering was utilized to measure particle size and particle size distribution. Results showed that morphology of self‐assembled supramolecular structures depended on molecular weight of backbone and pH value of media. By changing the self‐assembly conditions, different morphologies including spherical, Janus, and interconnected Janus were obtained.