Reentrant phase transition behavior and sensitivity enhancement of a molecular recognition ion gating membrane in an aqueous ethanol solution
Reentrant phase transition behavior and sensitivity enhancement of a molecular recognition ion gating membrane in an aqueous ethanol solution
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DOI：
10.1016/j.memsci.2009.11.028
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发表时间：
2010-02
影响因子：
9.5
通讯作者：
Taichi Ito;Yuhei Oshiba;H. Ohashi;Takanori Tamaki;Takeo Yamaguchi
中科院分区：
文献类型：
--
作者：
Taichi Ito;Yuhei Oshiba;H. Ohashi;Takanori Tamaki;Takeo Yamaguchi
研究了乙醇水溶液中分子识别离子门控膜对离子信号的响应行为。线性聚n-异丙基丙烯酰胺(NIPAM)-co-benzo -[18]-冠-6-丙烯酰胺（BCAm）共聚物在水和乙醇的混合溶剂中随乙醇摩尔分数的变化而发生相分离，称为回入式线圈-球-线圈转变。poly-NIPAM-co-BCAm的相图随特定离子信号浓度的变化而变化。基于这种重入式相变行为，将NIPAM和BCAm的共聚物接枝到多孔聚乙烯膜表面制备了门控膜，该门控膜通过接枝共聚物在乙醇水溶液中的膨胀和收缩来打开和关闭孔。此外，BCAm络合物形成常数随乙醇摩尔分数的增加而增大，增强了对离子种类的响应灵敏度和选择性；因此，在19.6mol%的乙醇水溶液中对bacl2的敏感性比在纯水中高10倍。
The response behavior of a molecular recognition ion gating membrane to an ion signal was investigated in an aqueous ethanol solution. The linear poly-N-isopropylacrylamide (NIPAM)-co-benzo[18]-crown-6-acrylamide (BCAm) copolymer showed phase separation in response to variation in ethanol mole fraction in the mixed solvent of water and ethanol, which is called a reentrant coil-to-globule-to-coil transition. The phase diagram of poly-NIPAM-co-BCAm changed in response to the concentration of a specific ion signal. Based on this reentrant phase transition behavior of the copolymer, the gating membrane, which was prepared by grafting the copolymer of NIPAM and BCAm onto the surface of a porous polyethylene film, opened and closed its pores by the swelling and shrinking of the grafted copolymer in an aqueous ethanol solution. In addition, the complex formation constant of BCAm increased with increasing ethanol mole fraction, which enhanced the response sensitivity and selectivity to ion species; thus, the sensitivity to BaCl2was 10 times higher in 19.6mol% aqueous ethanol solution than it was in pure water.