title: From Macromolecular to Small-Molecular Triggers: Facile Method toward Photoinduced LCST Phase Behavior of Thermoresponsive Polymers in Mixed Ionic Liquids Containing an Azobenzene Moiety.
abstract: Instead of the reported photoinduced lower critical solution temperature (LCST) phase transition behavior in ionic liquids (ILs) achieved by photofunctional polymers, this study reports the facile photoinduced LCST phase behavior of nonfunctionalized polymers (poly(benzyl methacrylate) (PBnMA) and poly(2-phenylethyl methacrylate) (PPhEtMA)) in mixed ILs (1,3-dimethylimidazolium bis(trifluoromethanesulfonyl)amide; [C1mim][NTf2] and a newly designed functionalized IL containing an azobenzene moiety (1-butyl-3-(4-phenylazobenzyl)imidazolium bis(trifluoromethanesulfonyl)amide; [Azo][NTf2])) as a small-molecular photo trigger. Interestingly, the length of the alkyl spacer between the ester and aryl groups, which is the only structural difference between the two polymers, leads to two different photoresponsive LCST phase transition behaviors. On the basis of spectroscopic studies, the different phase transition behaviors of PBnMA and PPhEtMA may attribute to the different cooperative interactions between the polymers and [C1mim][NTf2].
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Caihong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Kitazawa
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Shiguo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kokubo
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D015394:Molecular Structure; D008970:Molecular Weight; D055668:Photochemical Processes; D011108:Polymers / Q000737:chemistry*; D012996:Solutions; D013696:Temperature
chemical_list: D001391:Azo Compounds; D052578:Ionic Liquids; D046911:Macromolecular Substances; D011108:Polymers; D012996:Solutions; C009850:azobenzene
keywords: azobenzene; ionic liquids; phase separation; photochemistry; stimuli-sensitive polymers