No abstract

synthesized by the combination of ring-opening polymerization (ROP), dicyclohexylcarbodiimide (DCC) reaction and atom transfer radical polymerization (ATRP). After the quaternization reaction of the PDMAEMA segment with excess 1,3propane sultone, poly(ε-caprolactone)-SS-poly(3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate (SPCL-SS-PDMAPS) was obtained. The star-shaped structure of the copolymers and the presence of the amorphous PDMAEMA and PDMAPS in copolymers decreased or even completely suppressed the crystallizability of PCL in copolymers. These copolymers could self-assemble into spherical micelles in water. The thermoresponsive micelle solutions showed transition from a lower critical solution temperature (LCST) of SPCL-SS-PDMAEMA to an upper critical solution temperature (UCST) of SPCL-SS-PDMAPS, indicating that the LCST-UCST transition of the micellar solutions can be accomplished by the transition of PDMAEMA to PDMAPS. Moreover, the redox-responsive investigation showed that the distributions of hydrodynamic radius (Rh) broadened with the emergence of aggregates when DL-dithiothreitol (DTT) was added into the micellar systems, since the DTT would cause the breakage of disulfide bonds linking PCL and the PDMAEMA/PDMAPS blocks in copolymers.The micelles/aggregates that were self-assembled from star-shaped copolymer presented redox-responsive behaviour and LCST-UCST thermoresponsive transition.