Capacitive flexible pressure sensor based on porous GR/PDMS composite dielectric layer

Capacitive flexible pressure sensors, with the advantages of simple structure, reliable repeatability, and low energy consumption, have been widely used in wearable devices, soft robots, and other fields. This article describes the preparation of a polydimethylsiloxane (PDMS) sponge dielectric layer with a surface microstructure and dense internal bubbles by adding ammonium bicarbonate to PDMS, using sandpaper as a template, and utilizing the thermal decomposition of ammonium bicarbonate into three gases: ammonia, carbon dioxide, and water vapor (NH3, CO2, and H2O). Meanwhile, the sensitivity of the capacitive flexible pressure sensor using the sandwich structure with PDMS sponge can reach 0.4321 kPa−1 within the range of 0–3 kPa, and it has a fast response time and recovery time, good repeatability, and a wide detection range. The pressure sensor based on a porous graphene/PDMS (GR/PDMS) sponge dielectric layer can achieve human physiological signal detection and has broad application prospects in fields such as robot skin.