Temperature dependence of humido-responsive bending of conducting polymer films

The humido-responsive behavior of polypyrrole films at different temperatures under various humidities was investigated. The motion of film lay in the anisotropic expansion due to the sorption of water vapor from one side of the film, where the degree of bending was in proportion to the relative humidity change regardless of the temperature or absolute humidity. On the other hand, the film bent more quickly at higher temperatures, which was associated with the large diffusion coefficient for water vapor molecules in the film. The apparent activation energy in the sorption and desorption processes was found to be 46.0 kJ mol−1and 44.6 kJ mol−1, respectively.