Electromechanical Evaluation of Ionomeric Polymer-Metal Composites Using Video Analysis

Ionomeric Polymer-Metal Composites (IPMC) are smart materials whose electromechanical behavior depends on the electrical stimulus intensity, membrane hydration level, and ionic migration. This paper investigates the effects of the voltage, relative humidity, and counterion type (Li+ and K+ ) on a Nafion-based IPMC performance. Instrumentation capable of applying an electrical stimulus and measuring the electromechanical response was developed. The ionic conductivity was obtained using Electrochemical Impedance Spectroscopy. Complementary SEM analyses were performed before and after actuation cycles. The IPMC performance improved when the electrical stimulus was 5.00 V, RH = 90%, and Li+ was used. The IPMC-Li sample is an excellent candidate to be used as an actuator since it exhibited fast actuation movement, considerable displacement, and no evident back-relaxation. However, its mechanical performance decreased over time because of a progressive increase in platinum electrode crack density and dehydration. The video analysis technique is an efficient, effective, and low-cost technique.