Iontronic Pressure Sensor with Enhanced Sensitivity Empowered by Bioinspired Microstructures

High-performance capacitive pressure sensors are crucial for advancing wearable electronics and human-computer interaction, yet it remains challenging to simultaneously achieve high sensitivity and a broad linear working range. To overcome the inherent sensitivity-range trade-off in conventional designs, this work reports a confined evaporation strategy to fabricate the ionic dielectric layer featuring bioinspired microstructures for capacitive sensors. The dielectric layer mimics the surface morphology of Calathea zebrina leaves and spontaneously generates randomly distributed, pinecone-like microcones with a wide size distribution. Under external pressure, these microstructures demonstrate hierarchical deformation characteristics; smaller microcones activate preferentially under low pressure, while larger structures engage progressively with increasing load. This sequential engagement mechanism nonlinearly amplifies the effective contact area with electrodes. The expanded interfacial area synergizes with the electric double-layer effect from incorporated ionic liquid, substantially enhancing sensitivity, while the graded activation of different-sized microstructures enables an extended linear operating range. The flexible BC-MB electrode incorporates Ti3C2Tx MXene nanosheets with bacterial cellulose to form a conductive network, enhancing stability and sensitivity. The resulting capacitive sensor with flexible BC-MB electrodes achieves remarkable performance, ultrahigh sensitivity (692.30 kPa–1), wide linear response range, ultralow detection limit (0.53 Pa), fast response/recovery (61/32 ms), and excellent cycling stability (10,000 cycles). Meanwhile, this sensor demonstrates exceptional capability in capturing subtle physiological signals, including detailed arterial pulse waveforms for cardiovascular assessment, while enabling dual-mode human-computer interaction through Morse code gesture recognition and dynamic handwriting identification. Successful integration with wireless communication systems confirms its practical implementation potential in wearable health monitoring and interactive interfaces. This work establishes a scalable microstructure-engineering approach for high-performance capacitive sensors, effectively transcending conventional material-level constraints.