Development of Ion Sensors Based on Organic-Inorganic Composite as Membrane Materials

本研究构建了以有机-无机复合材料为膜材料的离子传感器。选择了溶胶-凝胶玻璃和介孔二氧化硅两种材料作为离子传感器的膜材料。1.基于溶胶-凝胶衍生膜的硫酸盐离子传感器合成了含有三乙氧基硅基和硫脲基团的化合物(1)。将化合物1加入到正硅酸乙酯(TEOS)和二乙氧基二甲基硅烷(DEDMS)的混合物中，通过水解、脱水和缩合反应，制得了化合物1化学改性的溶胶-凝胶膜。电极对硫酸盐离子的活度变化没有响应。另一方面，在硅橡胶作为膜材料的情况下，电动势响应几乎是能斯特的。2.基于Sol-Gel衍生膜的钙离子传感器合成了含有两个醚酰胺基和长链双键的化合物(2)，然后将两个三乙氧基硅基引入到化合物2(3)的Sol-Gel衍生膜中，并用化合物3对其进行化学修饰。基于介孔硅胶、十六烷基三甲基溴化铵和含三乙氧基硅基的16-冠-5衍生物的离子传感器制备了介孔二氧化硅，并用离子载体对其进行了化学修饰。将粉末状产物加入到TEOS和DEDMS的混合物中，采用溶胶-凝胶法制备了介孔二氧化硅薄膜。膜电极在较高的钠离子活度范围内表现出近能斯特响应。

In this study, ion sensors, which are based on organic-inorganic composite as membrane materials, were constructed. Two types of materials, sol-gel glass and mesoporous silica, were selected, and used for ion sensors as membrane materials.1.Sulfate ion sensors based on sol-gel derived membranesThe compound bearing a triethoxysilyl group and a thiourea group (1)was synthesized. Sol-gel derived membranes modified chemically with compounds 1 were prepared, by adding compound 1 into the mixture of tetraethoxysilane (TEOS) and diethoxydimethylsilane (DEDMS), through their hydrolysis, dehydration, and condensation. The electrodes did not respond to sulfate ion activity changes. On the other hand, in the case that silicone rubber was used as a membrane material, the EMF responses were almost Nernstian.2.Calcium ion sensors based on sol-gel derived membranesThe compound bearing two ether-amide groups and long alkyl chains with double bonds (2)was synthesized, and then, two triethoxysilyl groups were introduced into compound 2 (3)Sol-gel derived membranes encapsulating compound 2 and modified chemically with compounds 3 were prepared. Both membrane electrodes showed Nernstian responses to calcium ion activity changes.3.Ion sensors based on mesoporous silicaTEOS, cetyltrimethylammonium bromide, and 16-crown-5 derivative bearing a triethoxysilyl group were used, in order to prepare mesoporous silica which was chemically modified with ionophores. The powdery product was added into the mixture of TEOS and DEDMS, and, therefore, mesoporous silica membranes were formed by sol-gel method. The membrane electrodes showed near-Nernstian responses at higher range of sodium ion activities.