Title: Influence of Saturation Nonequilibrium and Variable Operation Conditions on the Electromechanical Performance of Ionic Polymer Metal Composite Actuator Architectures
Abstract: Electroactive polymers (EAPs) continue to gain attention for their potential to offer unique and versatile solutions in the soft robotic and flexible electronic industries. Ionic Polymer-Metal Composites (IPMCs) are a class of ionic-type EAPs which can be configured as capacitor actuators with very low voltage requirements (≤ 5 V AC or DC). Their compact, portable, and lightweight properties, coupled with a biomimetic bending actuation response make them ideal for human-machine integrated technologies such as medical implants, active skins, and artificial muscles. The Nafion-based IPMC can be described as a layered composite capacitor containing an ionic polymer core, sandwiched between chemically plated electrodes comprising of a conductive medium. Although there are reported achievements utilizing IPMCs in actuator configurations, their hydration-related sensitivity inhibits practical application in industry and makes experimental research difficult. This research sought to overcome these challenges by applying a wide range of experimental analyses, combined with theoretical modeling comparisons, to quantitatively characterize practical and standout factors impacting the actuator’s feasibility. The specific objectives investigated in this work include: (1) modifications of experimental test arrangements for practical insight; (2) investigation of IPMC degree of saturation and exposure correlations in both liquid and vapor conditions, coupled with electrical monitoring; (3) consideration of electrical field bias intensity and application arrangements on actuation behavior; and, finally, (4) practical inspection of IPMC design features and investigation of coating and geometric modification solutions for biomimetic and biocompatible applications.