High Specific Surface Area Pd/Pt Electrode-Based Ionic Polymer–Metal Composite for High-Performance Biomimetic Actuation

As biomimetic actuators that are operable under low voltages, ionic polymer–metal composites (IPMCs) have been proposed as promising candidates in the field of artificial muscles. In this study, a high specific surface area was obtained by directional roughening of a Nafion surface, and high-quality electrodes containing a Pd buffer layer and a Pt layer were deposited on the Nafion matrix via a method of isopropanol-assisted electroless plating, achieving outstanding electromechanical properties. The proposed IPMC exhibits an excellent tip displacement of 36.5 mm and a large blocking force of 2.4 MPa under a low direct current (DC) voltage. Furthermore, the IPMC has an excellent power density (up to 3966 J/m3) and can lift objects that are 20 times its weight, exhibiting great load capacity. More importantly, the imitation of biomimetic actuation behaviors including the opening/closing of petals and wing flapping of bees at a high frequency (21 Hz) has been demonstrated. The fabrication of high-quality Pd/Pt composite electrodes provides significant improvement for IPMC actuators, which is useful for their applications in medical devices and biomimetic robots.