Compression and shear mode ionic polymer-metal composite (IPMC) pressure sensors

Abstract

In this work, two types of dynamic pressure sensors based on ionic polymer-metal composites (IPMCs) in compression and shear deformation modes are designed, prototyped, and tested in a shock pressure tube. Although IPMCs offer appropriate properties such as flexibility, light weight, easy processing, resilience and high sensitivity to be used as sensors, there are only limited studies on applicable IPMC sensors and almost all of these devices were developed based on bending deformation. For a better understanding of the electromechanical sensing performance of the IPMCs, the charge current generation mechanisms due to external pressure in both compression and shear modes are developed based on the streaming potential hypothesis. The direct assembly process (DAP) is applied to fabricate some pressure sensor samples of each type for experimental evaluation. An equivalent circuit with parallel resistance and capacitance of the IMPCs samples, estimated by an impedance analyzer, is used to design an appropriate signal conditioner. A shock pressure tube setup is then utilized for performance evaluation of the fabricated devices. The results demonstrate that IPMCs as dynamic pressure sensors represent an appropriate linearity, sensitivity and consistency in both compression and shear modes. It is found that IPMC sensors in shear mode have a higher sensitivity compared with its compression mode counterpart.