Cleanroom-Free Fabrication of Flexible Capacitive Pressure Sensors Using Paintable Silver Electrodes on Stationery Paper and Random Microstructured PDMS Dielectric Layer

Abstract In this work, we propose a facile, low-cost, and cleanroom-free approach for flexible capacitive pressure sensors based on paintable Ag electrodes on stationery paper substrates (Ag-paper electrodes) and random microstructured PDMS dielectric layer transferred from emery paper. The COMSOL Multiphysics simulations and experimental investigations have suggested that the pressure sensor with random microstructured PDMS dielectric layer better performed the sensor with ordered micropyramidal dielectric layer. Developed Ag-paper electrode and random microstructured PDMS dielectric layer based pressure sensors are workable in a wide pressure range (up to 630 kPa), exhibited a high sensitivity of 0.132 kPa-1 up to 1 kPa, low hysteresis (6.6%) while loading-unloading of ~500 kPa pressure, high stability during ∼5250 cyclic test, and able to sense a low pressure of ∼27 Pa. The developed sensor is also successfully transduced arterial pulse wave form when it is properly attached on the wrist. Using the proposed process, a flexible capacitive pressure sensor matrix of 4×4 array is also successfully developed for single and multiple point pressure mapping with minimal cross-talk. The proposed sensor process is simple and inexpensive for implementation, and offers a spatial pressure mapping for e-skin application.