Electrochemornechanical deformation in polyaniline and poly(o-methoxyaniline)

pH dependencies of electrochemomechanical deformation (ECMD) and standard redox potential, E1/2 in poly(omethoxyaniline) (PmAn) have been studied between the states of leucoemeraldine and emeraldine salts. It is found that the magnitude of ECMD is constant of ca. 3% at pH > 2.0 and decreases gradually below the pH 2.O. The result is explained by the redox reactions of anion doping/dedoping process and proton exchange process at pH > 2.0 and pH < 2.0, respectively, taking the pH dependencies of E1/2 into consideration. A surprisingly large contraction ratio of more than 20% is obtained at the thickness direction of cast films in ECMD of polyaniline/HCl system. This fact is accounted by the anisotropic shrinking of cast film during the dry process.