Integrated Pressure and Proximity Sensors on Silicone and PU Substrates That Supports Flexible Hybrid Electronics

Abstract

In this work, we demonstrate an integrated, simple, yet highly sensitive parallel-plate and co-planar capacitive pressure sensors on a silicone-based composite substrate that addresses the issue of low surface energy (LSE) of silicone. The composite substrate exhibited flexibility and appropriate bonding strength after high-temperature vulcanization. Meanwhile, by utilizing deionized water in dielectric mixture (10%–30%), micropores in different sizes and distributions in the dielectric were realized as a novel solution to enhance its flexibility and thus its sensitivity. The parallel-plate pressure capacitor exhibited adjustable detection sensitivity between 5.3 and 6.6 kPa-1 and the highest sensitivity outperformed existing demonstrations in literature with large dynamic window between 0.05 and 83.3 kPa with a resolution of 0.05 kPa and a response time of 0.25 s. On the other hand, the co-planar proximity sensor showed supportiveness on real-time detection, exhibiting a multifunctional sensing system together with the parallel-plate pressure sensor. Related design, fabrication, evaluation, and discussion were thoroughly conducted in this work.