Electrochemical and Electromechanical Study of Carbon-Electrode-Based Ionic Soft Actuators

In the current work, metal-free Vulcan carbon/MWCNT (V/M) based soft actuators were fabricated by physical deposition of V/M ink on both faces of Nafion membrane. The effects of the weight percentage of MWCNTs on the electromechanical and electrochemical behaviors of actuators were studied through extensive experiments. Morphological characterization showed that the electrode structure of actuators changed considerably by changing the MWCNT content of the electrode layer. Electrochemical studies revealed V/M electrodes improve the ionic conduction and capacitive behavior of the Nafion-based actuators. The electrochemomechanical performance of actuators was compared by measuring maximum tip displacement, rate of displacement, durability, waveform analysis, and specific electromechanical energy efficiency. The highest tip displacement (44.5 mm) was obtained in actuators comprising 20 wt % MWCNTs. These actuators showed considerably higher ionic conductivity (26.9 mS/cm) and capacitive characteristic (45.2 μF cm –2 ) compared to the Pt-based actuators.