Highly Sensitive\nCapacitive Low-Pressure Graphene\nPorous Foam Sensors

Abstract

Flexible pressure sensors are becoming increasingly popular\ndue\nto their potential applications in multifunctional wearable devices.\nAmong flexible pressure sensors, capacitive pressure sensors based\non porous foams of poly­(dimethylsiloxane) (PDMS) are widely investigated.\nIn this work, we develop highly sensitive capacitive pressure sensors\noperating in a low-pressure range (<10 kPa) using graphene-coated\nPDMS foams with different ranges of pore sizes, obtained either by\nsugar templating or a combination of sugar templating and emulsion\ntemplating. Our analysis reveals that pressure sensors with the highest\nvariation in pore sizes over a wide pore size range are the most sensitive\nand reach a high sensitivity of ∼3.7 kPa^–1 (for a range of 2–6 kPa). These pressure sensors have a low\nlimit of detection of ∼20 Pa and are able to detect small changes\nin pressure in many situations, demonstrating potential applications\nin wearable biomedical sensors. Our result shows future pathways for\ndeveloping pressure sensors with higher sensitivities and, therefore,\nhighly relevant for research in pressure sensors based on conductive\nfoams.