High-k elastic composite dielectrics and microstructural engineering: high-sensitivity, ultra-wide linear range, and robust flexible capacitive pressure sensors for wearable electronics

Abstract

Flexible capacitive pressure sensors have emerged as essential components in diverse human–machine interaction (HMI) systems due to their facile fabrication, low power consumption and high stability. However, simultaneous achievement of high sensitivity and wide linear detection range remains a critical challenge in practical applications. In this study, high-performance flexible capacitive pressure sensors were developed through the synergistic integration of high-permittivity (high-k) elastic composites and rationally engineered microarchitectures. Non-covalently modified MWCNTs enabled uniform dispersion in TPU matrix, yielding a high-k TPU/MWCNT dielectric with tunable elasticity. Through electromechanical coupling simulations, an interlocked asymmetric pyramid structure (IAPM) that integrates multi-level contact dynamics was proposed to achieve linear capacitive response. The sensor achieved a high sensitivity of 0.0229 kPa⁻¹, an ultra-wide linear range of 0.1–1300 kPa, a fast response (≤100 ms), robust durability, and excellent environmental stability, thereby enabling its potential application in diverse fields, including bionic e-skin, athletic performance monitoring, and gait analysis. Additionally, a wearable plantar pressure monitoring system incorporating sensor arrays was developed to identify gait phase characteristics across diverse locomotion modes. This work has successfully overcome the sensitivity–detection range trade-off via material-structure synergy, offering a scalable pathway for next-generation flexible pressure sensors in healthcare and HMI technologies.