Flexible, Super-Stable, and Multifunctional Capacitive Pressure Sensors With Tilted Micropillar Array by Inclined Laser Ablation and Demolding

Abstract

Flexible capacitive pressure sensors have garnered considerable interest across diverse applications, including medical monitoring, electronic skin, and robotic tactile systems, owing to their straightforward fabrication process, low energy consumption, and robust stability. In this article, we introduce a new inclined laser ablation (ILA) combined with a demolding technique for the fabrication of flexible capacitive sensors featuring a microstructured dielectric layer composed of a tilted micropillar array (TMA). The design parameters of TMA were systematically optimized, including the tilt angle of the micropillars, array gap, aspect ratio, and bottom film thickness. The resulting capacitive pressure sensor, equipped with 75° TMAs (aspect ratio of 5:1), demonstrates exceptional sensitivity (1.12 kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula>) within the low-pressure range (0–2 kPa), rapid response and recovery times, a low-pressure detection limit of 0.25 Pa, and transient response stability factor (RSF) as high as 243.9. The proposed capacitive pressure sensor was validated for the detection and recognition of human motions when attached to various body parts. In addition, the sensors also demonstrated significant potential for diverse applications, including tactile sensing and Morse code communication.