Loofah Fiber Fabric-Based Piezoresistive Pressure Sensor with Wide-Linear-Range High Sensitivity

Abstract

Flexible pressure sensors are indispensable components of artificial tactile perception, whereas it remains a great challenge to possess high sensitivity and a wide linear response range simultaneously. Here, a plant fabric made of loofah fibers with excellent mechanical properties and intricate hierarchical porous structures is designed to replace the conventional soft materials as the sensing layer matrix, promoting structural compressibility while simultaneously providing enough conductive path with increasing pressure. Therefore, the loofah fiber fabric (LFF)-based piezoresistive pressure sensor exhibits high sensitivity (30.8 kPa⁻¹) and excellent linearity (R² = 0.990) over a wide pressure range (140 kPa), leading to an ultralow limit of detection (0.15 Pa) and ultrahigh pressure resolution (0.071%). Additionally, the LFF-based piezoresistive pressure sensor exhibits remarkable performance in the health monitoring of finger pulse and facial muscles, expression recognition, and multifunctional zone control. Furthermore, the loofah fiber is a low-cost and abundantly available natural material. Other biomaterials with excellent mechanical properties and hierarchical porous structures may also be suitable choices for tactile sensors calling for wide-linear-range high sensitivity.