The streaming potential method for modeling the electromechanical responses of ionic polymer transducers

Abstract

A streaming potential method for modeling the electromechanical responses due to imposed deformation of ionic polymer transducers (IPTs) is presented. It has been argued that imperfect ion pairing results in the availability of free counterions within the hydrophilic regions, thereby resulting in the presence of an electrolyte within these regions in the hydrophobic polymer matrix. When there is a net relative motion of this electrolyte with respect to the electrode, a streaming potential should result. It is hypothesized that a streaming potential mechanism within the electrode regions should be able to predict sensing responses for all modes of deformation. Based on a recently introduced parallel waterchannel morphology in Nafion® membrane, this model successfully addresses the physics of sensing in IPT bending. A linear relationship between the tip deflection of an IPT cantilever beam and the current generated in the IPT is achieved. The result trends show a good agreement with the experimental measurements. While this work studies the bending mode, it is able to be adapted for the other three sensing modes.