Achieving wide linear range and high sensitivity in capacitive pressure sensors via a stretchable nanofilm with interlocked hierarchy

Abstract

Capacitive pressure sensors have garnered significant attention in electronic skin, human-machine interaction, health monitoring and medical devices due to their remarkable properties like highly sensitive pressure perception, good repeatability, and rapid response capabilities. However, manufacturing capacitive pressure sensors that simultaneously achieve a broad linear detection range and high sensitivity remains a significant challenge. Herein, a novel hierarchically interlocked capacitive pressure sensor (HI-CPS) was designed by integrating the stretchable polyethylene glycol (PEG)-based nanofilm dielectric layer with hierarchically interlocked microstructures, which demonstrates excellent linearity and high sensitivity over a wide sensing range. HI-CPS based on a one-layer nanofilm exhibits ultrahigh sensitivity (9.40 kPa⁻¹) and an ultralow detection limit (0.1 Pa). When the dielectric layer comprises two layers of stacked nanofilms, the sensor not only maintains high sensitivity (3.17 kPa⁻¹) but also achieves excellent linearity (R² = 0.999) over a broad working range (<5 kPa), along with remarkable stability even after 10,000 cycles. Benefitting from the outstanding comprehensive performance, HI-CPS has been proven to be successfully implemented in monitoring various human biological signals, sign language recognition, and basketball shooting gesture correction. This strategy of assembling the tailored nanofilm with structural engineering has significant potential application in building high-performance pressure detection and recognition devices.

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