What happens at the ionomer-electrode interfaces and how it influences sensing and actuation in ionic polymer metal composites

Youngsu Cha, Maurizio Porfiri

Research output: Chapter in Book/Report/Conference proceedingChapter


The process of metal electrode deposition used in the fabrication of ionic polymer metal composites (IPMCs) results in the formation of a highly heterogeneous layer at the ionomer-electrode interfaces, whose conductive and dielectric properties may significantly differ from both the ionomer and the metal. Charge redistribution in the vicinity of such layers is often considered to be a determinant of IPMC charge dynamics and, thus, a key contributing factor to both actuation and sensing. In this chapter, we propose a refined modeling framework to understand what happens at these interfaces and predict the mechanics and electrochemistry of IPMCs. We describe the kinematics of an IPMC in terms of its mechanical deformation, the concentration of mobile counterions neutralizing the ionomer, and the electric potential. The chemoelectromechanical constitutive behavior is obtained from a Helmholtz free energy density, which accounts for mechanical stretching, ion mixing, and electric polarization. We demonstrate the approach in the analysis of three representative instances, namely: electrical response of IPMCs with fully covered electrodes at blocked null deformations; sensing dynamics of IPMCs with partially covered electrodes; and static actuation of IPMCs with perfect electrodes.

Original languageEnglish (US)
Title of host publicationIonic Polymer Metal Composites (IPMCs)
Subtitle of host publicationSmart Multi-Functional Materials and Artificial Muscles, Volume 2
EditorsMohsen Shahinpoor
PublisherRoyal Society of Chemistry
Number of pages16
StatePublished - 2016

Publication series

NameRSC Smart Materials
ISSN (Print)2046-0066
ISSN (Electronic)2046-0074

ASJC Scopus subject areas

  • Biotechnology
  • Biomedical Engineering
  • General Materials Science
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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