title: Liquid-liquid equilibria of polyrotaxane and poly(vinyl alcohol).
abstract: Liquid-liquid equillibria (LLE) of the tertiary system of hydroxypropylated polyrotaxane (HPPR)-poly(vinyl alcohol) (PVA)-solvent have been investigated by focusing on the internal structures of HPPR-PVA blend gels. The phase diagrams of the HPPR-PVA aqueous systems displayed two liquid phases at a high concentration and molecular weight of PVA. This result was consistent with the prediction of the Flory-Huggins lattice model. On the contrary, the HPPR-PVA-DMSO system exhibited only a single phase. The HPPR-PVA blend gels crosslinked in dimethylsulfoxide (DMSO) were highly transparent over a wide concentration range, while the gels prepared in water were opaque at high polymer concentrations. Spherical domains were observed in the opaque gels by laser scanning confocal microscopy, and the sizes of the domains were significantly dependent on the amount of cross-linking reagent utilized. These results indicated that the transparency of the HPPR-PVA blend gels was strongly affected by the competition between the liquid-liquid two-phase separation and the crosslinking HPPR and PVA polymers during the preparation of the blend gels.
authors.affiliation: Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5-603 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan. risuke@molle.k.u-tokyo.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kataoka
authors.forename: Yohei
authors.initials: Y
authors.lastname: Nagao
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kidowaki
authors.forename: Jun
authors.initials: J
authors.lastname: Araki
authors.forename: Kohzo
authors.initials: K
authors.lastname: Ito
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D003505:Cyclodextrins / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D005782:Gels; D018613:Microscopy, Confocal; D020442:Poloxamer / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D043862:Rotaxanes / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D005782:Gels; D043862:Rotaxanes; D012997:Solvents; C475673:polyrotaxane; D014867:Water; D020442:Poloxamer; D011142:Polyvinyl Alcohol; D004121:Dimethyl Sulfoxide