Flexible Capacitive Pressure Sensors With Conical-Protrusion Porous Microstructure for Human Health Monitoring

Abstract

Flexible capacitive pressure sensors exhibit significant potential for applications in wearable health monitoring, soft robotics, and human-computer interaction. However, achieving both high sensitivity and a wide response range simultaneously remains challenging. To address this, we designed a sensor incorporating a conical-protrusion porous microstructure inspired by the porous architecture of sponges. This structure enables a piecewise linear response across three distinct deformation stages: compression of the conical protrusions at low pressures, deformation of the porous framework at intermediate pressures, and bulk material densification at high pressures. This multi-stage mechanism effectively reconciles the sensitivity-range trade-off, yielding a sensor with high sensitivity (2.996 kPa⁻¹), a broad operational range (0–500 kPa), fast response time (98 ms), and durability exceeding 8,000 cycles under 300 kPa loading. Through demonstrations in human health monitoring and human-machine interaction, we highlight the sensor’s applicability to next-generation intelligent sensing systems. This work introduces a novel structural strategy for high-performance flexible capacitive pressure sensors, offering a pathway to balance sensitivity and dynamic range in flexible capacitive pressure sensors.