title: Thermoresponsive Poly(Ionic Liquid)s in Aqueous Salt Solutions: Salting-Out Effect on Their Phase Behavior and Water Absorption/Desorption Properties.
abstract: Here, a thermoresponsive phase behavior of polymerized ionic liquids (PILs) composed of poly([tri-n-alkyl(vinylbenzyl)phosphonium]chloride) (poly([Pnnn VB ]Cl) is reported, where n (the number of carbon atoms of an alkyl chain) = 4, 5, or 6 after mixing with aqueous sodium chloride solutions. Both monomeric [P555VB ]Cl and the resulting poly([P555VB ]Cl) linear homopolymer show a lower critical solution temperature (LCST)-type phase behavior in aq. NaCl solutions. The phase transition temperature of the PIL shifts to lower value by increasing concentration of NaCl. Also the swelling degree of cross-linked poly([P555VB ]Cl) gel decreases by increasing NaCl concentration, clearly suggesting the "salting-out" effect of NaCl results in a significant dehydration of the poly([P555VB ]Cl) gel. The absorbed water in the PIL gel is desorbed by moderate heating via the LCST behavior, and the absolute absorption/desorption amount is improved by copolymerization of [P555VB ]Cl with more hydrophilic [P444VB ]Cl monomer.
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories (FILL), Graduate School of Engineering, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Okafuji
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories (FILL), Graduate School of Engineering, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kohno
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories (FILL), Graduate School of Engineering, Tokyo University of Agriculture and Technology, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohno
mesh_terms: D065966:Absorption, Physicochemical; D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D063065:Organophosphonates / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D052578:Ionic Liquids; D063065:Organophosphonates; D011108:Polymers; D011145:Polyvinyls; D012996:Solutions; D014867:Water; D012965:Sodium Chloride
keywords: hydrogels; phase behavior; polyelectrolytes; swelling; transitions