Stalactite-Inspired Microstructures Synergizing with Embedded Interdigitated Electrodes for Wide-Range Piezoresistive Sensors

Flexible pressure sensors featuring surface microstructures are gaining increasing significance in diverse applications, such as health monitoring systems, smart wearable devices, and human–computer interaction. However, the inherent trade-off between high sensitivity and a broad detection range remains a significant challenge. To overcome this limitation, we developed a novel synergistic piezoresistive sensor incorporating stalactite-inspired microstructures and embedded interdigitated electrodes. The biomimetic stalactite microstructures are fabricated via polydimethylsiloxane (PDMS) replication of laser-ablated stainless steel microarrays with hierarchical microporous architectures. Subsequently, the microstructured surfaces are coated with multiwalled carbon nanotube (MWCNT) materials to form conductive sensitive layers for the pressure sensors. The embedded interdigitated electrodes are designed by integrating a UV-imprinted microchannel and an electrowetting-assisted blade-coating process of MWCNTs. The synergistic piezoresistive sensor achieves a wide detection range and high sensitivity (0.63 kPa – 1 in the low-pressure range of 0.18–120 kPa, and 0.16 kPa – 1 in the high-pressure range of 120–414 kPa). Furthermore, remarkable durability is exhibited even after undergoing 3000 compression–release cycles. The pressure sensor demonstrates versatile applicability, capable of detecting minute forces down to 0.3 g of static load, while simultaneously capturing complex motion dynamics including wrist movements, object gripping patterns, and full gait movement status in real time. The synergistic mechanism widens the detection range of the sensor and maintains high sensitivity, which provides a new strategy for manufacturing high-performance flexible pressure sensors.