Development of sensing/actuating ionic polymer–metal composite (IPMC) for active guide-wire system

Abstract

The potential for large deformation of the ionic polymer–metal composite (IPMC) is useful in the developments of biomedical device and miniature robot. The goal of this study is to investigate the feasibility of developing a sensing/actuating IPMC transducer as the head of an active guide-wire for cardiac catheterization. The approach employs an amplitude modulation–demodulation technique to obtain a deformation-sensing signal converted from the variation of electrical resistances in the IPMC electrodes. According to solvents and uptake conditions, three types of IPMC were produced and tested for the sensing and the actuating functions. Besides, a simulation of catheterization procedure was demonstrated with an IPMC guide-wire. From the estimated and the experimental results, the relationship between the sensing signal and the tip-displacement representing the deformation of the IPMC was verified. The sensing signal was proportional to the tip-displacement in the small deformation. The tests of the three types of IPMC showed that the sensitivity of deformation depended on the condition of material processing and solvent in IPMC. In addition, there was a trade-off between the sensing and the actuating functions of the IPMC. In the design of sensing/actuating IPMC, the electric power applied on the IPMC for actuation may interrupt the sensing signal with the migration of solvent in the IPMC. Differentiating the deformation-sensing signals between the deformed IPMC and an undeformed IPMC may alleviate the interference. The demonstration of a simulated catheterization exhibited the potential for sensing/actuating IPMC in checking the bifurcation of blood vessels without integrating a bulky sensor or adjusting the curvature of an IPMC-based active guide wire.