Highly compressible wearable sensor with CNT-coated PDMS sponge electrodes for tactile monitoring application

Abstract

Electrical resistance-based sensors have attracted great attention due to their wide range of applications, among which sensors for detecting external forces are indispensable due to the complex environment of the modern era. Inspired by the capillary phenomenon, in this study, we fabricated a carbon nanotube (CNT)-polydimethylsiloxane (PDMS)-based compressive resistive sensor that is easy to fabricate and has a wide range of sensitivities. Repeated compression tests were performed to evaluate the durability of the fabricated sensors. Different coating conditions resulted in different durability depending on the extent to which the CNT electrodes were coated on the porous PDMS surface, and the sensitivity of the sensors could be controlled by CNT concentration, coating time, and coating depth. Resistive sensors with different sensitivities can easily detect changes in electrical signals due to finger pressure, which shows great promise for use in wearable electronics. In addition, the resistive sensor is biocompatible because only the pure PDMS surface is attached to the human body, and the porous structure exhibits good compressibility.