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

Abstract

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.

A Nature-inspired Hierarchical Branching Structure Pressure Sensor for Medical Wearables

“…When compared with the previously reported pressure sensors based on multilayer or hierarchical structure, the proposed HB structure has a more significant effect on optimizing the sensitivity of the sensor. 26,38 This result can be attributed to the effective scheduling of microstructural deformation by the branching structure. Theoretically, the increased device thickness by this hierarchical structure might reduce the performance.…”

“…The high sensitivity of these sensors, however, is only valid in limited pressure regions because of the deformation saturation resulting from the elastic modulus. To address these limitations, several geometric microengineering strategies have been employed, including the use of hierarchical structures, 26 hollow structures, 27,28 novel geometric characteristics (e.g., Gaussian distribution rough surface, 29,30 plant leaves, 31 ), gradient conductivity and stiffness, 32 etc. However, new strategies to achieve a trade-off among the sensitivity, linearity range, easy of fabrication, active layer uniformity, shape and size versatility and tunability, and scalability of both the device and fabrication process for practical applications remain to be explored.…”

PI Film Laser Micro-Cutting for Quantitative Manufacturing of Contact Spacer in Flexible Tactile Sensor

“…Flexible tactile sensors are widely used in electronic skin [ 1 , 2 , 3 ], robots [ 4 , 5 , 6 ], wearable devices [ 7 , 8 , 9 ], etc. Depending on the source of the signal, the tactile sensors are classified into capacitive-type [ 10 , 11 ], piezoelectric-type [ 12 , 13 ], triboelectric-type [ 14 ] and piezoresistive-type [ 15 , 16 , 17 , 18 ]. Among them, the piezoresistive tactile sensor has been extensively studied for its advantages of simple structure, low manufacturing cost and convenient signal processing.…”

Bioinspired, Self-Powered, and Highly Sensitive Electronic Skin for Sensing Static and Dynamic Pressures

“…Wearable and flexible electronics, especially the self-powered sensors, are attracting unprecedented research interest due to their potential application in wearables. Among them, pressure sensors have potential applications in health monitoring, [1][2][3][4][5][6][7][8][9] human-machine interaction, [11][12][13][14] prosthetics, 15,16 and bio-inspired artificial nerves. 17,18 Based on various sensing mechanisms, different types of prevalent pressure sensing devices: capacitive, [19][20][21][22][23] piezoresistive, [24][25][26][27] piezoelectric, [28][29][30] and triboelectric sensors [31][32][33][34][35][36][37][38][39][40][41] have been reported.…”

“…Currently, tremendous efforts have been paid by the researchers in pursuing a high sensitivity and/or a broad pressure sensing range for piezoresistive pressure sensors but little attention has been paid in achieving self-powered piezoresistive devices. 3,11,12,49 Recently, He et al…”