We report here the development of an actuator with an ionic electroactive polymer (IEAP) laminate that is exclusively designed to exhibit a combination of high electrically induced strain and high bending modulus. The newly constructed laminate is one of the few IEAPs meeting the requirements for use in miniature soft robotics. The laminate has activated carbon-based electrodes and ionic liquid is used as an electrolyte. Layers of compliant gold foil are used as current collectors. The superior performance of the IEAP laminate is demonstrated by constructing a centimeter-scale robot propelled by a single IEAP actuator. The cyclic locomotion of the robot is inspired by the movements of an inchworm, while the IEAP laminate is used concurrently as an actuator and a structural member. The 830-mg robot is able to crawl on a smooth surface in open air, solely by undulation of its body. The microprocessor-controlled robot has an on-board lithium battery and uses a pulse-width-modulated signal to drive the IEAP actuator. The robot is able to carry its own power supply and even an extra payload. The constructed biomimetic robot is distinctive for the use of a non-planar actuator whose shape is programmed during the manufacturing process.

Ionic polymer metal composites (IPMCs) are electroactive material devices that bend at low applied voltage (1-4 V). Inversely, a voltage is generated when the materials are deformed, which makes them useful both as sensors and actuators. In this paper, we propose two new highly porous carbon materials as electrodes for IPMC actuators, generating a high specific area, and compare their electromechanical performance with recently reported RuO 2 electrodes and conventional IPMCs. Using a direct assembly process (DAP), we synthesize ionic liquid (Emi-Tf) actuators with either carbide-derived carbon (CDC) or coconut-shell-based activated carbon-based electrodes. The carbon electrodes were applied onto ionic liquid-swollen Nafion membranes using a direct assembly process. The study demonstrates that actuators based on carbon electrodes derived from TiC have the greatest peak-to-peak strain output, reaching up to 20.4 mε (equivalent to >2%) at a 2 V actuation signal, exceeding that of the RuO 2 electrodes by more than 100%. The electrodes synthesized from TiC-derived carbon also exhibit significantly higher maximum strain rate. The differences between the materials are discussed in terms of molecular interactions and mechanisms upon actuation in the different electrodes.

This article presents a novel model of an ionomeric polymer metal composite (IPMC) material. An IPMC is modeled as a lossy RC distributed line. Unlike other electro-mechanical models of an IPMC, the distributed nature of our model permits modeling the non-uniform bending of the material. Instead of modeling the tip deflection or uniform deformation of the material, we model the changing curvature. The transient behavior of the electrical signal as well as the transient bending of the IPMC are described by partial differential equations. By implementing the proper initial and boundary conditions we develop the analytical description of the possibly non-uniform transient behavior of an IPMC consistent with the experimental results.

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