title: Reversible thermoresponsive aggregation/deaggregation of water-dispersed polymeric nanospheres exhibiting structural transformation.
abstract: Crystalline polymeric nanospheres composed of poly{stearyl methacrylate (SMA)-co-poly(ethylene glycol) monomethacrylate (PEGm)}s were prepared by the dispersion radical polymerization of SMA and PEGm in an ethanol/water solution. Scanning electron microscopy showed that the nanospheres were highly spherical, and had a narrow size distribution. Electron spectroscopy for chemical analysis and X-ray diffraction studies of the nanospheres suggested a core-corona-type structure; the hydrophilic PEGm corona accumulated on the nanosphere surface, while the hydrophobic SMA core formed a layered structure. Heat treatment caused a melting of the SMA layers, but successive cooling allowed it to re-form. Accompanying this reversible order-disorder transition, the nanospheres also showed a reversible aggregation/deaggregation behavior in their water-dispersion state.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kaneko
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hamada
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kuboshima
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Akashi