A high-sensitivity and low-hysteresis flexible pressure sensor based on carbonized cotton fabric

Flexible pressure sensors have grown rapidly in the past few years. The great challenge for these sensors is the complex and expensive manufacturing process, as well as the electromechanical performance that is not compatible with sensitivity and hysteresis. In this work, a flexible resistive-type pressure sensor using carbonized cotton fabric (CCF) is manufactured through a facile, low-cost and scalable preparation process, which exhibits excellent flexibility and electromechanical performance. The composite material, obtained by immersing CCF in a thermoplastic urethane (TPU) solution, is combined with interdigitated electrodes to assemble the desired pressure sensor. The natural porous network of CCF with high-conductivity carbon fibers and the flexible substrate with low concentration TPU solution (resulting in reduced viscoelasticity) endow the flexible pressure sensor remarkable electromechanical performance, including ultrahigh sensitivity (up to 74.80 kPa−1) and ultralow hysteresis (3.39%), which are crucial for its practical application as flexible electronics. Moreover, the pressure sensor shows a large pressure range (0˜16 kPa), low detection limit (˜0.70 Pa) and excellent durability (>4000 cycles). Moreover, the influence of carbonization temperature on the electromechanical performance is also discussed. Based on the superior property of CCF/TPU pressure sensor, its applications in monitoring light items, wrist pulse, movements of fingers and wrists are demonstrated. Resultantly, low-cost raw materials, simple preparation processes and excellent electromechanical performance make the CCF/TPU pressure sensor a great potential in wearable flexible electronics.