Analytical Basis of ion separation by use of growth of conducting zones associated with electrochemical switching of conducting polymers

利用与导电聚合物电化学转换相关的导电区生长进行离子分离的分析基础

• 批准号: 06640777
• 负责人: AOKI Koichi
• 金额: $ 1.34万
• 依托单位: Fukui University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06640777/
• 关键词: conducting polymers; polyaniline films; hysteresis; Monte Carlo simulation; slow relaxation; in-situ measurements of conductivity; current induced by alteranating magnetic field; threshold of electric percolation; 電気化学的スイッチング; イオンの取り込み; 電気化学; イ

The electric conductivity of an aromatic conducting polymer film on an electrode can be altered drastically by varying the electrode potential in a dopant solution, because the doping and the undoping processes behave like an electrode reaction. When positive potential is applied to the film, the conducting zone grows and propagates from the electrode toward the solution until the film becomes the fully conducting state. The appearance of the phase boundary is ascribed to the electronic conduction of the oxidized species which works as a metal-like electrode for the electrochemical reaction with the reduced (insulating) species. This property may be sensitive to ionic species because ions are sensitive to the conduction state. This work has been devoted to application of this property to separation on ions. At first, the percolation threshold potential, which is significant for the switching behavior, was determined under quasistatic conditions. The was helpful for estimating potential domains of appearance of the conducting zone. Secondly, the inverse process was investigated with a help of spectroscopy, and was found to include slow relaxation. Thirdly, an interesting technique of evaluating electric conductivity by use of mgnetically induced current was found and developed. This was not predicted in advance, and is new information supported by this project. Forthly, study of the pH dependenae of the switching is going on now, which may lead to analysis of ion separation..

通过改变掺杂溶液中的电极电位，可以显著改变电极上芳香族导电聚合物膜的导电性，因为掺杂和非掺杂过程类似于电极反应。当向薄膜施加正电位时，导电区增长并从电极向溶液传播，直到薄膜变为完全导电状态。相界的出现归因于氧化物种的电子传导，氧化物种作为类金属电极与还原(绝缘)物种发生电化学反应。这一性质可能对离子物种敏感，因为离子对导电态很敏感。本工作致力于将这一性质应用于离子的分离。首先，在准静态条件下确定了对开关行为有重要意义的渗流阈值电势。这有助于估计导电区出现的潜在区域。其次，利用光谱学方法研究了反转过程，发现其包含慢弛豫现象。第三，发现并发展了一种有趣的利用磁感应电流来评估电导率的技术。这是事先没有预测到的，是这个项目支持的新信息。第四，对开关的pH依赖关系的研究正在进行中，这可能导致离子分离的分析。

项目成果

K.Aoki T.Edo and J.Cao: "Potential-step response of absorption at conducting to -insulating conversion of polyaniline films for demonstrating the slow relaxation" Electrochim..Acta. (in press).

K.Aoki T.Edo 和 J.Cao：“聚苯胺薄膜传导至绝缘转化时吸收的电位阶跃响应，用于证明缓慢弛豫”Electrochim..Acta。

Y.Tezuka: "Concentration distribution of conductagspecies with time resolution in electroclemical undcsing pioass'at the polypyrrole fclnt coated elctrode in the lohut of elictne persalation" J.Electroanalyticul Chemistry. 395. 51-55 (1995)

Y.Tezuka：“在电化学分析中，聚吡咯涂层电极上电导物质的浓度分布随时间分辨率的变化”J.Electroanalyticul Chemistry。

K. Aoki, J. Cao: "Capacitive-free ac impedance of polyanilial films by means of magneticully induced current" J. Electroanal. Chem.(in press). (1997)

K. Aoki，J. Cao：“通过磁感应电流实现聚苯胺薄膜的无电容交流阻抗”J. Electroanal。

Y.Tezuka: "Dispersion of intefece of conducting/insulating zone tomporarily generatid in a polypyrroletilm" I.Electroamlytical Chemistry. (発表予定). (1996)

Y.Tezuka：“聚吡咯钛中暂时生成的导电/绝缘区域的分散”I.Electroamlytical Chemistry（待提交）。

J. Cao, K. Aoki: "Percolation threshold potentials at quasi-static electrochemical switching of polyaniline films" Electrochim. Acta. 41. 1787-1792 (1996)

J. Cao，K. Aoki：“聚苯胺薄膜准静态电化学开关的渗透阈值”Electrochim。