Ueki Takeshi, Yamaguchi Ayuko, Ito Naoki, Kodama Koichi, Sakamoto Junji, Ueno Kazuhide, Kokubo Hisashi, Watanabe Masayoshi
Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
Langmuir. 2009 Aug 18;25(16):8845-8. doi: 10.1021/la901159r.
4-phenylazophenyl methacrylate (AzoMA) and benzyl methacrylate (BnMA) were copolymerized to produce multistimuli-responsive polymers (P(AzoMA-r-BnMA)s) in a hydrophobic ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([C2mim][NTf2]), as the solvent. P(AzoMA-r-BnMA)s with a maximum of ca. 4 mol % AzoMA were soluble in [C2mim][NTf2] at low temperatures, and they underwent lower critical solution temperature (LCST) phase separation with an increase in temperature. Under UV and visible light irradiation, P(AzoMA-r-BnMA)s underwent reversible photochromism of trans-to-cis and cis-to-trans isomerization, respectively. The LCST temperature differences between trans- and cis-form polymers in the IL were as large as 22 degrees C. Reversible photoinduced phase separation of the polymers was achieved at a certain temperature; at this temperature, the cis-form polymers were soluble in the IL, but the trans-form polymers were not.
4-苯基偶氮苯基甲基丙烯酸酯（AzoMA）和苄基甲基丙烯酸酯（BnMA）在疏水性离子液体（IL）1-乙基-3-甲基咪唑双（三氟甲烷磺酰）亚胺（[C2mim][NTf2]）作为溶剂的条件下进行共聚，以制备多刺激响应聚合物（P(AzoMA-r-BnMA)s）。含有最高约4摩尔％AzoMA的P(AzoMA-r-BnMA)s在低温下可溶于[C2mim][NTf2]，并且随着温度升高会发生下临界溶液温度（LCST）相分离。在紫外光和可见光照射下，P(AzoMA-r-BnMA)s分别经历反式到顺式和顺式到反式异构化的可逆光致变色。IL中反式和顺式聚合物之间的LCST温度差高达22℃。在一定温度下实现了聚合物的可逆光诱导相分离；在此温度下，顺式聚合物可溶于IL，但反式聚合物不溶。
