An alternative explanation of back-relaxation in ionic polymer metal composites

M. Porfiri, A. Leronni, L. Bardella

Research output: Research - peer-reviewArticle

Abstract

The phenomenon of back-relaxation in ionic polymer metal composites (IPMCs) has attracted the interest of the scientific community for two decades, but its physical origins largely remain elusive. Here, we propose an explanation of this phenomenon based on Maxwell stress. From first principles, we demonstrate that IPMC actuation is controlled by the nonlinear interplay between osmotic and electrostatic phenomena. While osmotic pressure tends to produce a rapid bending toward the anode, Maxwell stress generates a slow relaxation toward the cathode. The relative weight of these phenomena is determined by the applied voltage. At voltage levels comparable to the thermal voltage, IPMC actuation is dominated by osmotic effects. As the applied voltage is increased, Maxwell stress overcomes the osmotic pressure, leading to back-relaxation.

LanguageEnglish (US)
Pages78-83
Number of pages6
JournalExtreme Mechanics Letters
Volume13
DOIs
StatePublished - May 1 2017

Fingerprint

Polymers
Metals
Composite materials
Electric potential
Electrostatics
Anodes
Cathodes
Hot Temperature

Keywords

  • Actuator
  • Electrochemistry
  • Maxwell stress
  • Poisson–Nernst–Planck

ASJC Scopus subject areas

  • Bioengineering
  • Chemical Engineering (miscellaneous)
  • Engineering (miscellaneous)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

An alternative explanation of back-relaxation in ionic polymer metal composites. / Porfiri, M.; Leronni, A.; Bardella, L.

In: Extreme Mechanics Letters, Vol. 13, 01.05.2017, p. 78-83.

Research output: Research - peer-reviewArticle

@article{e2dca9c00de945888ee0fa245c7c6dde,
title = "An alternative explanation of back-relaxation in ionic polymer metal composites",
abstract = "The phenomenon of back-relaxation in ionic polymer metal composites (IPMCs) has attracted the interest of the scientific community for two decades, but its physical origins largely remain elusive. Here, we propose an explanation of this phenomenon based on Maxwell stress. From first principles, we demonstrate that IPMC actuation is controlled by the nonlinear interplay between osmotic and electrostatic phenomena. While osmotic pressure tends to produce a rapid bending toward the anode, Maxwell stress generates a slow relaxation toward the cathode. The relative weight of these phenomena is determined by the applied voltage. At voltage levels comparable to the thermal voltage, IPMC actuation is dominated by osmotic effects. As the applied voltage is increased, Maxwell stress overcomes the osmotic pressure, leading to back-relaxation.",
keywords = "Actuator, Electrochemistry, Maxwell stress, Poisson–Nernst–Planck",
author = "M. Porfiri and A. Leronni and L. Bardella",
year = "2017",
month = "5",
doi = "10.1016/j.eml.2017.01.009",
volume = "13",
pages = "78--83",
journal = "Extreme Mechanics Letters",
issn = "2352-4316",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - An alternative explanation of back-relaxation in ionic polymer metal composites

AU - Porfiri,M.

AU - Leronni,A.

AU - Bardella,L.

PY - 2017/5/1

Y1 - 2017/5/1

N2 - The phenomenon of back-relaxation in ionic polymer metal composites (IPMCs) has attracted the interest of the scientific community for two decades, but its physical origins largely remain elusive. Here, we propose an explanation of this phenomenon based on Maxwell stress. From first principles, we demonstrate that IPMC actuation is controlled by the nonlinear interplay between osmotic and electrostatic phenomena. While osmotic pressure tends to produce a rapid bending toward the anode, Maxwell stress generates a slow relaxation toward the cathode. The relative weight of these phenomena is determined by the applied voltage. At voltage levels comparable to the thermal voltage, IPMC actuation is dominated by osmotic effects. As the applied voltage is increased, Maxwell stress overcomes the osmotic pressure, leading to back-relaxation.

AB - The phenomenon of back-relaxation in ionic polymer metal composites (IPMCs) has attracted the interest of the scientific community for two decades, but its physical origins largely remain elusive. Here, we propose an explanation of this phenomenon based on Maxwell stress. From first principles, we demonstrate that IPMC actuation is controlled by the nonlinear interplay between osmotic and electrostatic phenomena. While osmotic pressure tends to produce a rapid bending toward the anode, Maxwell stress generates a slow relaxation toward the cathode. The relative weight of these phenomena is determined by the applied voltage. At voltage levels comparable to the thermal voltage, IPMC actuation is dominated by osmotic effects. As the applied voltage is increased, Maxwell stress overcomes the osmotic pressure, leading to back-relaxation.

KW - Actuator

KW - Electrochemistry

KW - Maxwell stress

KW - Poisson–Nernst–Planck

UR - http://www.scopus.com/inward/record.url?scp=85011995399&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85011995399&partnerID=8YFLogxK

U2 - 10.1016/j.eml.2017.01.009

DO - 10.1016/j.eml.2017.01.009

M3 - Article

VL - 13

SP - 78

EP - 83

JO - Extreme Mechanics Letters

T2 - Extreme Mechanics Letters

JF - Extreme Mechanics Letters

SN - 2352-4316

ER -