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Behaviors of polyaniline artificial muscle under high tensile loads have been studied. The artificial muscle based on the electrochemomechanical deformation exhibits a large creep under high tensile loads. However, the creep is recovered by the removal of tensile loads and several electrochemical cycles. The facts indicate that the creep is due to the one dimensional anisotropic deformation. The anisotropic deformation is retained by the ionic crosslink at the oxidized state, and released by the cycling under load free.

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Electrochemomechanical deformation (ECMD) of the conducting polymer polyaniline film is studied to investigate the behaviour of actuation under tensile loads. The ECMD was induced by the strains due to the insertion of ionic species (cyclic strain) and a creep due to applied loads during the redox cycle. The cyclic strain was enhanced by the experience of high tensile loads, indicating a training effect. The training effect was explained by the enhanced electrochemical activity of the film. The creep was recovered by removal of the tensile load and several electrochemical cycles. This fact indicates that the creep results from the one-dimensional anisotropic deformation, and is retained (shape retention) by the ionic crosslink. The recovery of creep results from the elastic relaxation of the polymer conformation.

Electrochemomechanical deformations (ECMD) of conducting polymer, polyaniline, films are studied to investigate the creeping and the memory effects. During electrochemical cycling under high tensile stresses up to 5 MPa, the films showed a remarkable creeping, resulting in the one dimensional anisotropic deformation. However, the creeping was recovered by release of the tensile stress, restoring from the anisotropic deformation. It was also found that the strain of ECMD after applying high tensile stresses increased compared with that before applying the large tensile stress. The result indicates that the artificial muscles are strengthened in strain by the experience of large tensile loads, and discussed taking the rheology of electrochemical cycles, viz., electrostatic crosslinking of polymer chains by oxidation and release of crosslinking by reduction.