Self-assembly of multiple stimulus response copolymer by ATRP in different media

The novel pH and thermo-sensitive amphiphilic triblock copolymer poly(methyl methacrylate)-block-poly(N-isopropylacrylamide)-block-poly[N,N-(dimethylamino) ethyl methacrylate] (PMMA-b-PNIPAM-b-PDMAEMA) was synthesized by ATRP. We have prepared the AB amphiphilic copolymer (PMMA-b-PNIPAM) and ABC amphiphilic triblock copolymer (PMMA-b-PNIPAM-b-PDMAEMA) of expected molecular mass. It was characterized by GPC,(HNMR)-H-1 and FT-IR spectroscopy. The AB amphiphilic copolymer ability of temperature response and the morphology of self-assembly micelles different in toluene, THF, and DMF. ABC amphiphilic triblock copolymer self-assembled petal structure in alkaline aqueous solution, and lamellar structure in acidic aqueous solution. Moreover, the transmittance of micellar solution changes with the increase of temperature; these changes reflect the pH and thermo-sensitivity of the block copolymer. The micelles behavior and morphology of the system were studied by transmission electron microscopy (TEM) and dynamic light scattering (DLS).