Chapter 6: Ionic Polymer Metal Composites with Electrochemically Active Electrodes
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Published:19 Nov 2015
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U. Johanson, A. Punning, and A. Aabloo, in Ionic Polymer Metal Composites (IPMCs)
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The vast majority of the aqueous ionic polymer metal composite (IPMC) materials are fabricated with electrodes made of precious metals—gold or platinum. At first glance this may seem unreasonable, since there are several well-known metal plating methods using the substantially cheaper metals—copper or silver. In point of fact, an IPMC is a complicated electrochemical system in which the occurrence of the electrochemical processes depends on the applied voltage. In aqueous-based IPMCs, the electrolysis of water occurs at higher voltages. Due to the various electrochemical factors, the presence of a non-precious metal in an IPMC changes its behaviour drastically. On the one hand, it opens up new possibilities for better actuation. On the other hand, in the presence of non-precious metals, the unwanted side-reactions (e.g. the corrosion of electrodes) already occur at very low voltages. This chapter highlights the electrochemical aspect of IPMCs with electrodes made of precious metals as well as copper, silver, and nickel.