High surface area electrodes in ionic polymer transducers

Abstract

Ionomeric polymer transducers have received considerable attention in the past ten years due to their ability to generate large bending strain and moderate stress at low applied voltages. Ionic polymer transducers consist of an ionomer, usually Nafion, sandwiched between two electrically conductive electrodes. Recently, a novel fabrication technique denoted as the direct assembly process (DAP) enabled controlled electrode architecture in ionic polymer transducers. A DAP transducer usually consists of two high surface area electrodes made of uniform distributed particles sandwiching an ionomer membrane. Further enhancements to the DAP enabled sub-micron control of the electrode architecture. In this study a previously developed finite element model, capable of simulating ionic polymer transducers with high surface area electrodes is used to study the effect of electrode architecture on the actuation performance due to a unit volt step input. Four architectures are considered: Agglomerate, Gradient, Random, and Lines. The four architectures are simulated for low particle loading and high particle loading. The agglomerate presents the case of badly dispersed metal particles in the electrode. Simulation results demonstrate that particle aggregation reduces the actuation performance on an IPT. The Gradient simulates an IPT built using an Impregnation-Reduction method. The Gradient is compared to a randomly distributed electrode which represents an IPT built using the DAP method. Simulation results demonstrate that the DAP built IPT outperforms the one built using the impregnation-reduction method. Finally line architecture is simulated and results demonstrate that it outperforms random architecture especially at high particle loading.