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

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 of silicone. The composite substrate exhibited flexibility and appropriate bonding strength after high-temperature vulcanization. Meanwhile, by utilizing de-ionized water in dielectric mixture (10% to 30%) micro pores in different sizes and distributions in the dielectric was 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 kPa -1 to 6.6 kPa -1 and the highest sensitivity outperformed existing demonstrations in literatures with large dynamic window between 0.05 kPa to 83.3 kPa with a resolution of 0.05 kPa and 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.