Multiple morphologies of a poly(methyl methacrylate)-block-poly(N,N-dimethyl aminoethyl methacrylate) copolymer with pH-responsiveness and thermoresponsiveness

We successfully prepared a series of pH-responsive and thermoresponsive poly(methyl methacrylate) (PMMA)-block-poly(N,N-dimethyl aminoethyl methacrylate (PDMAEMA) copolymers via reversible addition-fragmentation chain-transfer polymerization with PMMA as a macro chain-transfer agent. Control over the chain length of PDMAEMA allowed the morphological transformation of PMMA-b-PDMAEMA. The critical water content and critical micelle concentration also depended on the length of the PDMAEMA block. UV-visible and fluorescence spectrum analyses indicated that the PMMA-b-PDMAEMA copolymer exhibited a lower critical solution temperature type phase transition in water. The particle size of PMMA-b-PDMAEMA was dominated by the pH value, as evidenced by dynamic light scattering and transmission electron microscopy. In addition, the PMMA-b-PDMAEMA copolymers exhibited good reversible thermoresponsive behavior between 33 and 38 degrees C. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47972.