Synthesis and pH/Temperature-Responsive Behavior of PLLA-b-PDMAEMA Block Polyelectrolytes Prepared via ROP and ATRP

Well-defined diblock poly(L-lactide)-block-poly(dimethylamino-2-ethyl methacrylate) (PLLA-b-PDMAEMA) copolymers were synthesized by combining ROP of LLA and ATRP of DMAEMA, from a dual-initiator 2-hydroxylethyl 2-bromoisobutyrate. The molecular characterization of these diblock copolymers was performed using (1)H NMR, FT-IR, and GPC-MALLS analysis. The responsive behavior of these diblock copolymers in aqueous solutions at different pH and temperatures were investigated using DLS. Results show that both higher pH and temperature result in a higher degree of neutralization, weaker hydrogen bonding, and micellar aggregation. As observed by TEM, changes in micellar morphology are in accordance with DLS results.