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Title: Comparative experimental investigation on the actuation mechanisms of ionic polymer–metal composites with different backbones and water contents

Water-based ionic polymer–metal composites (IPMCs) exhibit complex deformation properties, especially when the water content changes. To explore the general actuation mechanisms, both Nafion and Flemion membranes are used as the polymer backbones. IPMC deformation includes three stages: fast anode deformation, relaxation deformation, and slow anode deformation, which is mainly dependent on the water content and the backbone. When the water content decreases from 21 to 14 wt. %, Nafion–IPMC exhibits a large negative relaxation deformation, zero deformation, a positive relaxation deformation, and a positive steady deformation without relaxation in sequence. Despite the slow anode deformation, Flemion–IPMC also shows a slight relaxation deformation, which disappears when the water content is less than 13 wt. %. The different water states are investigated at different water contents using nuclear magnetic resonance spectroscopy. The free water, which decreases rapidly at the beginning through evaporation, is proven to be critical for relaxation deformation. For the backbone, indirect evidence from the steady current response is correlated with the slow anode deformation of Flemion-IPMC. The latter is explained by the secondary dissociation of the weak acid group –COOH. Finally, we thoroughly explain not only the three deformations by swelling but also their evolvement with decreasing water content. A fitting model ismore » also presented based on a multi-diffusion equation to reveal the deformation processes more clearly, the results from which are in good agreement with the experimental results.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2]
  1. State Key Laboratory of Mechanical Structure Strength and Vibration, Xi'an Jiaotong University, Xi'an 710049 (China)
  2. (China)
  3. Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577 (Japan)
  4. Niumag Corporation, Shanghai 200333 (China)
  5. School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)
Publication Date:
OSTI Identifier:
22271145
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ANODES; COMPOSITE MATERIALS; DIFFUSION EQUATIONS; DISSOCIATION; ELECTRIC CURRENTS; EVAPORATION; HUMIDITY; MEMBRANES; METALS; NUCLEAR MAGNETIC RESONANCE; POLYMERS; RELAXATION; SWELLING; WATER