FABRICATION OF CHEMOMECHANICAL ACTUATORS USING CONDUCTING POLYMERS.

本研究的目的是阐明导电聚合物在电化学氧化/还原过程中发生化学机械变形的机理，即导电聚合物在电化学氧化/还原过程中的膨胀和收缩，并利用导电聚合物制作执行器。1997年，我们研究了导电聚合物聚苯胺在不同阴离子水溶液中的化学机械变形程度、响应和作用力。结果表明：(1)大体积阴离子的掺杂和不掺杂；(2)聚合物的离域构象变形；(3)阳离子间的静电斥力。在这些机制中，(1)占主导地位，但(2)或(3)被认为对变形起作用。1998年，我们研究了自掺杂聚苯胺和含有大阴离子的聚苯胺，以阐明机制(2)和(3)的存在。合成了自掺杂的磺酸型聚苯胺，并对其进行了循环伏安和化学机械形变测试。在氧化过程中，一旦膜膨胀，然后收缩，处于准平衡状态。用pi电子的离域或多阳离子间的静电斥力来解释这种膨胀。在氧化还原反应过程中，聚苯胺膜在恒流模式下与樟脑磺酸(CSA)大阴离子聚合形成聚苯胺膜，发现CSA阴离子在氧化还原反应过程中能将CSA阴离子保留在膜中。结果表明，在氧化过程中，由于机理(2)和(3)的作用，薄膜轻微膨胀，甚至有质子被排除在薄膜之外。

Purposes of the study are to clarify mechanisms of chemomechanical deformation, i.e.expansion and contraction of conducting polymers upon electrochemical oxidation/reduction, and to fabricate actuators using conducting polymers.In 1997, the degree, response and force of chemomechanical deformation in conducting polymer, polyaniline were investigated in various anions of aqueous solution. As results, mechanisms of deformation are found to be (1) doping and undoping of bulky anions, (2) conformational deformation of polymer resulted from delocalization of and (3) electrostatic repulsion between polycations. In these mechanisms, (1) is found to be predominant, however, (2) or (3) is suggested to play a role for the deformation.In 1998, self-doped polyaniline and polyaniline with giant anions are studied to elucidate the existence of mechanisms (2) and (3). Sulfonic polyaniline which is self-doped was synthesized and measured in the cyclic voltammogram and chemomechanical deformation. In the oxidation process, once the film expands followed by contraction at the quasi-equilibrium state. The expansion is explained by taking the delocalization of pi electrons or electrostatic repulsion between polycations. Then, structural relaxation takes place by the strong negative sulfonic ion, which attracts pi electrons of benzene ring, resulting in shrinking of polymer film.Polyaniline film polymerized by constant current mode with a giant anion of camphor sulfonic acid (CSA) was found to keep CSA anion in film during the redox reactions. the result indicates that during oxidation process the film slightly expand due to mechanism (2) and (3), even protons are excluded from the film.