Effective Fabrication of Graphene-Coated Ionic Polymer Membrane Actuators

Ionic polymer-metal composites (IPMCs) are promising soft actuators; however, they face challenges such as solvent evaporation, low blocking force, and complex fabrication processes. This study introduces a simplified method for fabricating ionic polymer-graphene composite (IPGC) actuators using Nafion 117 membranes and graphene powder. Graphene was directly rubbed onto the membrane surface and subjected to brief microwave irradiation to form durable electrodes, eliminating the need for solvents, multilayer casting, or expensive metal plating. The experimental results indicated that repeated fabrication cycles reduced surface resistance and enhanced bending performance, with optimal displacement achieved after three cycles. Scanning electron microscopy confirmed improved adhesion and surface uniformity following microwave treatment. A hybrid electromechanical model, combining an RC circuit with a mass-spring-damper system, was developed to accurately predict the static behavior of the actuator and achieve reliable parameter estimation. Although the bending performance of the ionic polymer actuator fabricated using the proposed method reaches approximately 75% of that of conventionally produced IPMCs, the method offers a significantly simpler and lower-cost fabrication process.