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Dielectric properties of hydrated or dehydrated ionic gels

水合或脱水离子凝胶的介电性能

基本信息

批准号：
10640494
负责人：
SASAKI Shigeo
金额：
$ 2.18万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640494/
关键词：
Volume phase tansition NIP gel Dielectric dispersion Ionic NIPA gel

项目摘要

A system for the dielectric measurement has been made. The system is well designed to controll the temperature and to shield the electric wave during the measurement. A cell adapting to the gel has been developed. The dielectric spectra in the frequency range between 0.1Hz and 1MHz are obtained when the conductance of test sample is less than 1uS.The polymer gels of N-isopropylacrylamide, into which a small amount of ionic styrensulfonate(0.5mo1%: NIPA-SS5 ; 0.1mo1% : NIPA-SS1 ; Omo1%: NIPA)is introduced, have been synthesized and their dielectric properties have been examined by using the measuring system mentioned above. The temperature dependence of diffusion coefficients of small ions in the gel has been examined by using the method which we have developed(Bull. Chem. Soc. Jpn., 69, 2173-2178(1996)). From these measurements, the followings have been clarified. 1)The diffusion coefficient of small ion in the collapsing NIPA gel is one hundredth of that in the swelling gel. 2)The conductance of the collapsing gel is also about one hundredth of the swelling gel. 3)The dielectric dispersions are observed in the low(10Hz-100Hz)and high (1MHz)frequency regions for any of NIPA NIPA-SS5 gels in the collapsing state. 4)The NIPA=SS1 and NIPA-SS5 gels in the swelling state exhibit the dispersions around 0.2MHz but the NIPA gel in the swelling state doesn't. These results strongly indicate that the water molecules in the collapsing gels are electrically disconnected or disperse as isolated clusters(like the water molecules in oil). The result of 3)suggests that the strong ion-pair forms between the ionic group on the gel chain and the counter ion in the collapsing gels and that the relaxation frequency of structured water in the hydrated state is between 10Hz and 100Hz. These results have been published as a full paper and a part of them has been submitted.

已经制作了介电测量系统。该系统设计良好，可以控制温度并屏蔽测量过程中的电波。已经开发出适应凝胶的细胞。当测试样品的电导小于1uS时，获得了0.1Hz至1MHz频率范围内的介电谱。引入少量离子型苯乙烯磺酸盐(0.5mo1%：NIPA-SS5；0.1mo1%：NIPA-SS1；Omo1%：NIPA)的N-异丙基丙烯酰胺聚合物凝胶。合成并使用上述测量系统检查了它们的介电性能。使用我们开发的方法检查了凝胶中小离子扩散系数的温度依赖性(Bull.Chem.Soc.Jpn., 69, 2173-2178(1996))。根据这些测量结果，可以明确以下几点。 1)小离子在塌缩NIPA凝胶中的扩散系数是在溶胀凝胶中的百分之一。 2）塌陷凝胶的电导率也约为溶胀凝胶的百分之一。 3)任何NIPA NIPA-SS5凝胶在塌陷状态下均在低频(10Hz-100Hz)和高频(1MHz)区域观察到介电色散。 4)溶胀状态下的NIPA=SS1和NIPA-SS5凝胶在0.2MHz附近表现出色散，而溶胀状态下的NIPA凝胶则没有。这些结果强烈表明，塌陷凝胶中的水分子在电上断开或分散为孤立的簇（如油中的水分子）。 3)的结果表明，在凝胶链上的离子基团和塌陷凝胶中的抗衡离子之间形成强离子对，并且水合状态下结构水的弛豫频率在10Hz和100Hz之间。这些结果已作为全文发表，部分结果已提交。