Improved fabrication and tests of a CNT/PANI composite film actuator

Many efforts to develop an innovative actuator which consist of SWNTs and conducting polymer have been made for last several years for its possible application to operate MEMS devices or small insect-like robots. In this nanocomposite film actuator, the SWNTs electrodes exhibit a unique pore structure and high efficiency of specific surface areas, which can be considered as the surface-area-enhancing component in composite films. Therefore, the composite pseudocapacitance is increased remarkably. This large capacitance suggests that the composite film can be used for local energy storage as well as actuation. Carbon nanotubes have high electrical conductivity that can increase the charging-discharging rate and improve the electrodic performance of conducting polymers films. SWNTs also exhibit strains due to electrochemical redox at low bias voltage (non-Faradic electrochemical charging), which is enough for actuating MEMS devices. In addition, SWNTs show very high Young's modulus so that they can function as reinforcing fibers to the conducting polymers matrix in the composite actuator. As a result, it is possible to make a SWNTs/CPs composite actuator that can show both high actuation strain and high available stress. SWNTs/CPs film actuator was fabricated and the strain was measured. The original length was 1₀=12.69mm. The extension was measured by the laser displacement meter, Δ1=0.043mm.