A Novel Tubular Thin-Wall IPMC Sensor Capable of Two-Dimensional Sensing: Fabrication, Characterization and Modeling

An ionic polymer-metal composite (IPMC) sensor typically consists of a thin ion-exchange membrane with electrodes on both surfaces. Such IPMC sensors respond to deflections in the beam-bending directions only and thus are considered one-dimensional. In this paper, a novel IPMC sensor capable of two-dimensional sensing is presented. This tubular thin-wall IPMC has one common inner electrode and four outer electrodes, which form four routes of common-ground outputs. The fabrication method is reported along with the sensor package. A custom-designed experimental setup, which provides dynamic tip bending with adjustable orientations and controlled bending amplitude, is used to characterize the sensor response (short-circuit current) to the 2D mechanical stimulus in air. Based on the characterization results, we further model the proposed 2D tubular IPMC sensor by treating pairs of infinitesimal portion of tube wall as one-dimensional IPMC sensors and integrating them around the tube. Experimental results show that the fabricated IPMC sensor responds to omnidirectional stimulus within the cross-section plane and the proposed model captures well the sensor responses, indicating that this tubular IPMC sensor can be potentially used for 2D flow and displacement sensing.