Actuators based on pedot and PPy conducting polymer bilayers and trilayers

The demand for actuators based on conducting polymers is growing due to their highly desirable features such as large mechanical strength, high power density, sufficient maximum strain values, high reversibility and good safety properties. Many attempts have been made to improve the actuator performance. We report here some electromechanical measurements on actuators of bilayer and trilayer free standing films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers. These multi layer films were prepared electrochemically so that the PEDOT layer is very thin compared to that of the PPy layer. The films were characterized electromechanically under constant load of 1.5 g. Results were compared with that of the PPy single layer film. Bilayer film shows a significant increase in the strain measured at higher scan rate ( > 100 mV s^-1). The force generation between reduced and oxidized states is much higher for trilayer films and higher for bilayer films than that in a single layer of PPy. These differences are not linked to the Youngpsilas modulus of these films. The addition of a thin PEDOT does not change Youngpsilas modulus, but changes the force generation significantly.