A flexible and highly sensitive capacitive pressure sensor with fast response based on a hierarchically micro-structured PDMS dielectric layer

Abstract

Flexible high-sensitivity pressure sensors have seen rapid growth in the last few years in applications like electronic skin, smart wearables and medical health monitoring. In this work, we develop a high-flexibility capacitive pressure sensor design based on a hierarchical, micro-pyramid-structured dielectric layer of polydimethanes. The goal of this design is to achieve low-hysteresis capacitive pressure sensors with increased sensitivity and reduced response time. To optimize the performance of the proposed pressure sensor, we designed and fabricated several different micro-pyramid structures on the silicon template using standard photolithography and anisotropic etching. As a result, the pressure sensor with a hierarchical micro-pyramid structure achieved through graphic transfer has the best performance, with a sensitivity of up to 2.64 kPa−1 (0–2 kPa), a response time of 45 ms, a low limit of detection of < 8 Pa, and high stability over at least 1200 loading cycles. As a result of these remarkable performance features, the pressure sensor proposed can be effectively utilized for the detection of physiological signals as well as mechanical pressure which can be widely used in the fields of motion sensing, health monitoring and intelligent robots.