Interlocked Hemispherical−Conical Porous Dielectric Layers for High-Sensitivity and Wide-Range Capacitive Pressure Sensing

Abstract

Flexible capacitive pressure sensors demand high sensitivity across a broad detection range to simultaneously capture subtle physiological signals and macroscopic mechanical stimuli. Nevertheless, dielectric layers engineered to enhance low-pressure sensitivity typically suffer from structural densification and response saturation under high pressure, resulting in an inevitable trade-off between sensitivity and sensing range. Herein, we present a flexible capacitive pressure sensor featuring a rationally designed poly(dimethylsiloxane)/multiwalled carbon nanotube (PDMS/MWCNT) composite dielectric layer. This layer utilizes an interlocking double-layer architecture characterized by interlaced hemispherical and conical protrusions alongside internal pores. Under compression, this structure undergoes stepwise deformation via local contact enhancement, interlayer interlocking, and pore collapse, thereby enhancing the capacitive response across a broad pressure range. Consequently, it enables multiscale monitoring, ranging from subtle physiological signals to robust joint motions and gripping forces. Furthermore, a chair-integrated 3 × 5 sensor array achieved low-crosstalk spatial pressure mapping and recognized five typical sitting postures with 98.82% accuracy. This work offers a powerful structural strategy for broad-range intelligent pressure sensors, promising for diverse human−machine interaction applications.