A Method to characterize the deformation of an IPMC sensing membrane

Ionic polymer metal composites (IPMCs) are emerging materials used to realize motion sensors and actuators. In the former case by bending an IPMC membrane a voltage output is obtained, while in the latter case a voltage input is able to cause the membrane to bend. Although a number of interesting properties have been described for such materials, few results have been obtained regarding their characterization. In this paper a system devoted to the characterization of IPMCs as motion sensors is presented. The system was built in order to study the IPMC reaction, in a large range of frequencies, to a mechanical bending stimulus, in a cantilever configuration. An IPMC strip acts as the movable capacitive plate between two fixed plates, inside a differential capacitive measuring system. The motion of the IPMC is transduced into the system output voltage, without any mechanical contact, while ad-hoc electronics detect the IPMC sensing output voltage. A description of the IPMC characterization system follows a brief introduction to IPMC behaviour as sensors and actuators. Then, steps devoted to evaluation of the relationship between the input displacement forced to the IPMC being tested and the corresponding IPMC voltage output are derived