All-Textile Electronic Skin Enabled by Highly Elastic Spacer Fabric and Conductive Fibers

Abstract

Electronic fabrics that combine traditional fabric with intelligent functionalities have attracted increasing attention. Here an all-fabric pressure sensor with a wireless battery-free monitoring system was successfully fabricated, where a 3D penetrated fabric sandwiched between two highly conductive fabric electrodes acts as a dielectric layer. Thanks to the good elastic recovery of the spacer fabric, the capacitance pressure sensor exhibits a high sensitivity of 0.283 KPa −1 with a fast response time and good cycling stability (≥20 000). Water-soluble poly(vinyl alcohol) template-assisted silver nanofibers were constructed on the highroughness fabric surface to achieve high conductivity (0.33 Ω/sq), remarkable mechanical robustness, and good biocompatibility with human skin. In addition, the coplanar fabric sensor arrays were successfully designed and fabricated to spatially map resolved pressure information. More importantly, the gas-permeable fabrics can be stuck on the skin for wireless real-time pressure detection through a fiber inductor coil with a resonant frequency shift sensitivity of 6.8 MHz/kPa. Our allfabric sensor is more suitable for textile technology compared with traditional pressure sensors and exhibited wide potential applications in the field of intelligent fabric for electronic skin.

Simultaneous Sensing of Touch and Pressure by Using Highly Elastic e-Fabrics

“…The sensors are evaluated in an overview comparison with other existing works. Our sensors have a sensitivity higher than two studies, (0.283 kPa −1 at 5 kPa) [26] and (121 × 10 −4 kPa −1 at 100 kPa) [48], and lower than two studies (0.007 kPa −1 at 5 kPa) [34,49]. Our sensors also have a lower thickness than those studies, as shown in Figure 8.…”

“…Otherwise, the outputs are easily influenced by parasitic capacitance. The spacer layer, by PET yarns of the spacer fabric, will improve the elasticity of the electrodes, thereby increasing the sensitivity of the sensor for flexible applications in wearable research [26,43,44]. The capacitance at the pressing point (C) can be calculated by Equation 1, where A represents electrode area, d represents dielectric thickness, ε 0 represents a constant for the dielectric permittivity of vacuum, and ε r represents the permittivity of a dielectric.…”

“…You et al [25] presented an e-skin tactile sensor matrix pixelated by position-registered conductive microparticles. Ronghui et al [26] researched a textile electronic skin enabled by a highly elastic spacer fabric and conductive fibers. However, limitations still exist in such studies such as insensitivity under touching without pressure, too high a sensitivity for large pressure applications, limited air permeability, or complex fabrication.…”

“…The manufacturing process, as shown in Figure 1, allows for rapid, reliable, and scalable production of large sensor sheets. As this process just focuses on printing the layers, it is simpler than other existing works [26,34]. Otherwise, the screen-printing technologies are easy to approach and apply in industry.…”

Electron-Induced Perpendicular Graphene Sheets Embedded Porous Carbon Film for Flexible Touch Sensors

“…More importantly, micro-/nano-structure in the elastomeric electrode is thought to be a key element of sensor devices [21][22][23][24], providing faster response time, and higher sensitivity compared to the unstructured electrode [25,26]. Therefore, structured graphene-based sensors have potential to possess superior performance [27].…”