Mechanoelectric transduction of ionic polymer-graphene composite sensor with ionic liquid as electrolyte

Abstract

In this paper, an ionic polymer-graphene film composite (IPGC) sensor comprised of an ionic polymer membrane sandwiched between two graphene electrodes was demonstrated, the mechanoelectrical properties were investigated on home-built experimental setup and a physical mechanoelectrical model that takes ion transportation into account was presented using Comsol Multiphysics software for numerical simulations. Scanning electron microscope observation shows that the graphene electrode is tight coupling with chitosan polymer. Experimental verification indicates that as the frequency of input displacement increases from 2 to 10 Hz, the voltage output increases from 2.95 to 13.56 mV under the peak-to-peak amplitude of sinusoidal vibration of 2 mm. Compared with conventional ionic polymer metal composite (IPMC) sensor, IPGC in this work generates 2.74∼4.52 times higher output voltage, which is attributed to high initial cation concentration (∼4250 mol/m3), and IPGC shows the relatively stable mechanoelectrical property because of the crackless graphene electrode and the stable ionic liquid. Model analysis shows that a fair agreement between the simulated and measured data is achieved and the peak-to-peak amplitude of the generated voltage increases with the increasing frequency in the range from 2 to 10 Hz with the increase rate about 1.2–1.4 mV/Hz. This paper provides the understanding of the mechanoelectrical transduction mechanism and property, which can be used for development of sensors and energy harvesters.