Fabrication and characterization of a two-dimensional IPMC sensor

Ionic polymer-metal composites (IPMCs) have inherent sensing and actuation properties. An IPMC sensor typically consists of a thin ion-exchange membrane, chemically plated 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 proposed by plating two pairs of electrodes on orthogonal surfaces of a Nafion beam that has comparable thickness and width. The fabrication method is reported along with the characterization of the fabricated sensor. Experimental results show that the proposed IPMC sensor can be used for 2D flow sensing with promising applications in artificial lateral line systems. In the fabrication process Nafion solution is first cast and solidified, and the resulting structure is then cut to form beams with square cross-sections. In particular, the sample we fabricated has cross section of 1mm by 1mm and length of 15mm. Platinum electrodes are then plated on four side surfaces of the Nafion beam, insulated from each other. The fabricated IPMC sensor is shown to respond to 2D mechanical stimuli, and separate sensor signals are collected from the two pairs of electrodes. The responses (short-circuit currents) of the fabricated IPMC sensor are characterized both in air and in water, to verify the 2D sensing capability and examine the correlation between the two sensor signals.