Wang Caihong, Ma Xiaofeng, Kitazawa Yuzo, Kobayashi Yumi, Zhang Shiguo, Kokubo Hisashi, Watanabe Masayoshi
Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
Macromol Rapid Commun. 2016 Dec;37(23):1960-1965. doi: 10.1002/marc.201600360. Epub 2016 Sep 22.
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; [C mim][NTf ] and a newly designed functionalized IL containing an azobenzene moiety (1-butyl-3-(4-phenylazobenzyl)imidazolium bis(trifluoromethanesulfonyl)amide; [Azo][NTf ])) 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 [C mim][NTf ].
本研究报道了非功能化聚合物（聚甲基丙烯酸苄酯（PBnMA）和聚甲基丙烯酸2-苯乙酯（PPhEtMA））在混合离子液体（1,3-二甲基咪唑鎓双（三氟甲磺酰）酰胺；[C mim][NTf₂]和一种新设计的含偶氮苯部分的功能化离子液体（1-丁基-3-（4-苯基偶氮苄基）咪唑鎓双（三氟甲磺酰）酰胺；[Azo][NTf₂]））中作为小分子光引发剂时容易实现的光致最低临界溶液温度（LCST）相转变行为，而不是通过光功能聚合物在离子液体（ILs）中报道的光致LCST相转变行为。有趣的是，酯基和芳基之间烷基间隔基的长度，这是两种聚合物之间唯一的结构差异，导致了两种不同的光响应LCST相转变行为。基于光谱研究，PBnMA和PPhEtMA不同的相转变行为可能归因于聚合物与[C mim][NTf₂]之间不同的协同相互作用。
