A Novel Thermoresponsive Hydrogel with Ion-Recognition Property through Supramolecular Host-Guest Complexation

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• 作者：Xiao-Jie Ju ; Liang-Yin Chu ; Li Liu ; Peng Mi ; Young Moo Lee
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：January 31, 2008
• 年：2008
• 卷：112
• 期：4
• 页码：1112 - 1118
• 全文大小：317K
• 年卷期：v.112,no.4(January 31, 2008)
• ISSN：1520-5207

文摘

A novel thermoresponsive hydrogel with ion-recognition property was prepared via free-radical cross-linkingcopolymerization of N-isopropylacrylamide (NIPAM) with benzo-18-crown-6-acrylamide (BCAm) as hostreceptor. Both chemical structures and stimuli-sensitive properties of the prepared poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) P(NIPAM-co-BCAm) hydrogel were characterized. The smart hydrogelcould respond to both temperature and ion stimuli. When the crown ether units captured Ba²⁺ and formedstable BCAm/Ba²⁺ host-guest complexes, the lower critical solution temperature (LCST) of the hydrogelincreased due to the repulsion among charged BCAm/Ba²⁺ complex groups and osmotic pressure within thehydrogel. Whereas crown ethers captured Cs⁺, the LCST shifted to a lower temperature because of the formationof 2:1 sandwich complexes. Unexpectedly, the LCST of the cross-linked P(NIPAM-co-BCAm) hydrogel inK⁺ solution did not shift to a higher temperature, which was definitely different from the previously reportedlinear P(NIPAM-co-BCAm) copolymer in K⁺ solution. The results of this work provide valuable informationfor development of dual thermo- and ion-responsive hydrogels which have potential applications in drugcontrolled-release systems or biomedical fields.