Abstract
Random, graft, and block amphiphilic copolymers were prepared by a combination of 2-(dimethylamino)ethyl methacrylate as the hydrophilic monomer and styrene as the hydrophobic one. The temperature-transmittance curves of 1.0%(w/v) copolymer solutions [10%(v/v) MeOHaq. with sodium dodecyl sulfate added] were measured by an UV-vis spectrophotometer at a fixed wavelength (500 nm). The temperature-transmittance curves of random copolymer solutions shifted to the lower temperature zone with an increase in composition ratio of styrene monomer, whereas those of graft and block copolymer ones showed an unchanged lower critical solution temperature (LCST) regardless of the ratio of styrene monomer. However, the decreasing in transmittance was observed at clear temperature zone below the LCST, and the temperature-transmittance curves at cooling stage shifted to the lower temperature zone, compared with ones at the heating stage. Moreover, at opaque temperature zone above the LCST, the order of average particle size of dispersed polymer was as follows: block copolymer>random ones>graft ones.
