Template‐free Formation of Hybrid Dielectric for Flexible Capacitive Sensors with Wide‐Pressure‐Range Linear Detection

Abstract

Wearable and flexible capacitive pressure sensors have recently attracted significant attention in the fields of healthcare monitoring and intelligent human‐machine interaction. While considerable progress is made in achieving high‐pressure resolution over a wide linearity range, practical implementation still faces significant challenges due to complex manufacturing processes, as well as limited accuracy and stability for information transmission. To address these issues, inspiration is drawn from human skin and develop a new hybrid dielectric comprising a low‐permittivity (low‐k) micro‐cilia array and a high‐permittivity (high‐k) foam. Without assistance from an elaborate fabrication methodology, the template‐free method provides a cost‐effective and convenient way to realize the functional dielectric for flexible capacitive sensors. The hybrid dielectric exhibits a pressure‐induced series‐parallel conversion mechanism, enabling effective manipulation of the linear effective dielectric constant and controlled initial/resultant capacitance. Through systematic optimization, the sensor demonstrates a high sensitivity of 0.236 kPa−1 within an ultrabroad linearity range of up to 1100 kPa. Thanks to the unique characteristics of the hybrid dielectric, this device showcases potential applications in various domains including human joint motion analysis, healthcare monitoring, accurate message transmission, and convenient Morse code communication utilizing non‐overlapping capacitance signals.