TY - JOUR
T1 - Modelling compression sensing in ionic polymer metal composites
AU - Volpini, Valentina
AU - Bardella, Lorenzo
AU - Rodella, Andrea
AU - Cha, Youngsu
AU - Porfiri, Maurizio
N1 - Funding Information:
Work financed by the Italian Ministry of Education, University, and Research (MIUR), and by the National Science Foundation under Grant Number OISE-1545857. A Rodella and V Volpini thank the H2CU Center and the University of Brescia for the financial support during their stay at the New York University Tandon School of Engineering.
Publisher Copyright:
© 2017 IOP Publishing Ltd.
PY - 2017/2/13
Y1 - 2017/2/13
N2 - Ionic polymer metal composites (IPMCs) consist of an ionomeric membrane, including mobile counterions, sandwiched between two thin noble metal electrodes. IPMCs find application as sensors and actuators, where an imposed mechanical loading generates a voltage across the electrodes, and, vice versa, an imposed electric field causes deformation. Here, we present a predictive modelling approach to elucidate the dynamic sensing response of IPMCs subject to a time-varying through-the-thickness compression ('compression sensing'). The model relies on the continuum theory recently developed by Porfiri and co-workers, which couples finite deformations to the modified Poisson-Nernst-Planck (PNP) system governing the IPMC electrochemistry. For the 'compression sensing' problem we establish a perturbative closed-form solution along with a finite element (FE) solution. The systematic comparison between these two solutions is a central contribution of this study, offering insight on accuracy and mathematical complexity. The method of matched asymptotic expansions is employed to find the analytical solution. To this end, we uncouple the force balance from the modified PNP system and separately linearise the PNP equations in the ionomer bulk and in the boundary layers at the ionomer-electrode interfaces. Comparison with FE results for the fully coupled nonlinear system demonstrates the accuracy of the analytical solution to describe IPMC sensing for moderate deformation levels. We finally demonstrate the potential of the modelling scheme to accurately reproduce experimental results from the literature. The proposed model is expected to aid in the design of IPMC sensors, contribute to an improved understanding of IPMC electrochemomechanical response, and offer insight into the role of nonlinear phenomena across mechanics and electrochemistry.
AB - Ionic polymer metal composites (IPMCs) consist of an ionomeric membrane, including mobile counterions, sandwiched between two thin noble metal electrodes. IPMCs find application as sensors and actuators, where an imposed mechanical loading generates a voltage across the electrodes, and, vice versa, an imposed electric field causes deformation. Here, we present a predictive modelling approach to elucidate the dynamic sensing response of IPMCs subject to a time-varying through-the-thickness compression ('compression sensing'). The model relies on the continuum theory recently developed by Porfiri and co-workers, which couples finite deformations to the modified Poisson-Nernst-Planck (PNP) system governing the IPMC electrochemistry. For the 'compression sensing' problem we establish a perturbative closed-form solution along with a finite element (FE) solution. The systematic comparison between these two solutions is a central contribution of this study, offering insight on accuracy and mathematical complexity. The method of matched asymptotic expansions is employed to find the analytical solution. To this end, we uncouple the force balance from the modified PNP system and separately linearise the PNP equations in the ionomer bulk and in the boundary layers at the ionomer-electrode interfaces. Comparison with FE results for the fully coupled nonlinear system demonstrates the accuracy of the analytical solution to describe IPMC sensing for moderate deformation levels. We finally demonstrate the potential of the modelling scheme to accurately reproduce experimental results from the literature. The proposed model is expected to aid in the design of IPMC sensors, contribute to an improved understanding of IPMC electrochemomechanical response, and offer insight into the role of nonlinear phenomena across mechanics and electrochemistry.
KW - electrochemistry
KW - finite deformations
KW - finite element method
KW - ionic polymer metal composites
KW - matched asymptotic expansions
KW - sensing
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U2 - 10.1088/1361-665X/26/3/035030
DO - 10.1088/1361-665X/26/3/035030
M3 - Article
AN - SCOPUS:85014768010
VL - 26
JO - Smart Materials and Structures
JF - Smart Materials and Structures
SN - 0964-1726
IS - 3
M1 - 035030
ER -