All-Fabric Tactile Sensors Based on Sandwich Structure Design with Tunable Responsiveness

Abstract

Capacitance tactile sensors (TSs) based on electrode distance and contact area variations have been notably employed for various purposes due to their magnificent stress sensitivity. Nevertheless, developing TSs with tunable responsiveness in a broad pressure interval is crucial owing to the trade-off between sensitivity and linear identification range. Herein, a TS including Ag-coated Velcro and spacer fabric is constructed, where its sandwich framework provides a sizable expansion in compression deformation ability. In addition, a multilayered framework composed of the stacked TS from self-adhesive Velcro provides more contact area and significant deformation for stress distribution, further balancing the sensitivity, sensing range, and linearity for smart garment application. By utilizing the overlaid selection of multilayer structures, the all-textile TS demonstrates outstanding sensitivity with a one-layer structure (0.036 kPa^-1) over a pressure range of 0.2-5 kPa and retains a sensitivity of 0.002 kPa^-1 in a four-layer structure over a wide pressure range of 0.2-110 kPa, representing a significant improvement compared to previous results. The sensor possesses excellent performance in terms of response speed (104 ms), repeatability (10,000 cycles), and flexibility. In addition, its significant applications, involving human motion detection, pliable keyboards, and human-computer interface, are successfully shown. Based on the facile and scalable manufacturing approach, a suitable procedure is presented to construct next-generation wearable electronics.