Cost-Efficient Formation of Flexible Pressure Sensor with Micropillar Arrays by Metal-Assisted Chemical Etching for Wearable Electronic Skin

Wearable flexible pressure sensor as an important research direction of the electronic skin, which has great application prospect in tactile sensors, artificial intelligence, and bio implant devices. Pressure sensors using the piezoresistive property have the advantages of a simple device structure and easy read-out mechanism when measuring the pressure caused by the variation in the resistance. Constructing microstructures is an effective approach to improve the sensitivity of the sensors. Most of reported microstructures of flexible pressure sensors were fabricated based on photolithography, which relied on expensive equipment, complicate and time-consuming processes. However, these processes are complicated, expensive and hard to large area produce. In this paper, we propose a facile method for the formation of pressure sensors which are integrated by two flexible Au-coated PDMS films with interlocked micropillars arrays. The micropillars arrays were simply fabricated by a novel wet Si etching method of metal-assisted chemical etching (MACE) with the assistance of polymer colloid self-assembly technique. The as-prepared flexible pressure sensor exhibits high sensitivity of ~0.6 kPa
^-1
in low pressure regime of 0-250 Pa. This work provides a simple approach for low-cost and large area fabrication of flexible pressure sensor with high performance.