Sensing mechanical deformation via ionic polymer metal composites: A primer

Ionic polymer metal composites (IPMCs) were discovered about twenty five years ago by Prof. Oguro and his team in Japan [1], and evidence about metalizing ionomer membranes dates even earlier [2]. Since their discovery, IPMCs have been the object of intensive research across the entire globe [3]-[5]. In its simplest form, an IPMC is constituted by a hydrated ionomeric membrane (that is, an electrically-charged polymer), which is neutralized by mobile counterions in a solution and plated by noble metal electrodes. IPMCs can be used as actuators and sensors, whereby a voltage applied across the electrodes will elicit mechanical deformation, and an imposed mechanical deformation will induce a measurable voltage across the electrodes.