Multi-Layered, Hierarchical Fabric-Based Tactile Sensors with High Sensitivity and Linearity in Ultrawide Pressure Range

Resistive tactile sensors based on changes in contact area have been extensively explored for a variety of applications due to their outstanding pressure sensitivity compared to conventional tactile sensors. However, the development of tactile sensors with high sensitivity in a wide pressure range still remains a major challenge due to the trade-off between sensitivity and linear detection range. Here, a tactile sensor comprising stacked carbon nanotubes and Ni-fabrics is presented. The hierarchical structure of the fabrics facilitates a significant increase in contact area between them under pressure. Additionally, a multi-layered structure that can provide more contact area and distribute stress to each layer further improves the sensitivity and linearity. Given these advantages, the sensor presents high sensitivity (26.13 kPa(-1)) over a wide pressure range (0.2-982 kPa), which is a significant enhancement compared with the results obtained in previous studies. The sensor also exhibits outstanding performances in terms of response time, repeatability, reproducibility, and flexibility. Furthermore, meaningful applications of the sensor, including wrist-pulse-signal analysis, flexible keyboards, and tactile interface, are successfully demonstrated. Based on the facile and scalable fabrication technique, the conceptually simple but powerful approach provides a promising strategy to realize next-generation electronics.