A flexible highly sensitive capacitive pressure sensor

Flexible pressure sensor has been increasingly recognized over the past several decades, but there is still a challenge to fabricate it with a superb sensitivity and large sensing range. Herein, a highly flexible, sensitive and capacitive pressure sensor based on a porous ionic membrane is developed. The innovative sensor contains a polyvinyl alcohol/potassium hydroxide (PVA/KOH) porous ionic dielectric layer and two indium tin oxide polyethylene terephthalate (ITO-PET) films, which are coated on the top and bottom of the dielectric layer, respectively. The sensing mechanism of the sensor is based on the electric double layer capacitors between ITO-PET electrodes and PVA/KOH membrane. By improving the deformability of such elastomer dielectric layer with micro-pores, the sensitivity is greatly enhanced and the detectable range of pressure is significantly widened. Comparing to traditional pressure sensor, the developed sensor provides a high sensitivity up to 20.83/kPa and rapid dynamic responses (50 ms) for pressure measurement. More importantly, the sensor is insensitive to the bending deformation and stable in a low temperature range. Furthermore, a capacitive sensor network is fabricated to measure the spatial pressure distribution and magnitude.