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/还原作用下的化学力学变形，即膨胀和收缩的机理，并利用导电聚合物制造致动器。1997年，研究了导电聚合物聚苯胺在不同阴离子水溶液中的化学力学变形程度、响应和力。结果发现，变形机制是：(1)大块阴离子的掺杂和脱掺杂；(2)聚合物的离域引起的构象变形；(3)聚阳离子之间的静电排斥。在这些机制中，(1)被发现是主要的，然而，(2)或(3)被认为对变形起作用。1998年，研究了自掺杂聚苯胺和巨阴离子聚苯胺的存在机制(2)和(3)。合成了自掺杂的磺酸聚苯胺，并对其循环伏安和化学力学变形进行了测定。在氧化过程中，薄膜一旦膨胀，紧接着在准平衡状态下收缩。用π电子的离域或多阳离子间的静电斥力来解释膨胀。然后，强负的磺酸离子引起结构弛豫，吸引苯环上的π电子，导致聚合物薄膜收缩。用恒流模式聚合的聚苯胺膜在氧化还原反应中保持了大阴离子樟脑磺酸（CSA）在膜内的存在。结果表明，在氧化过程中，由于机理(2)和(3)，膜略有膨胀，甚至质子被排除在膜外。

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.