Carbon Nanotube Fiber Assemblies With Braided Insulation Layers For Washable Capacitive Textile Touch Sensors

Capacitive textile touch sensors were developed using carbon nanotube (CNT) fiber assemblies with braided insulating fibers, considering the washability, a critical factor to realize smart clothing. CNT fibers with electrical conductivity comparable to that of metal wires were fabricated by wet-spinning of purified single-walled CNTs. An insulation layer was then introduced into the CNT fiber assembly, to fabricate capacitive conductive fibers through a braiding process of insulating polymeric fibers. The effects of braiding on the insulation and washability of the conductive fibers were investigated to identify the optimal braiding configuration with respect to the insulation, electrical conductivity, and tensile strength properties of the fibers. The change in capacitance of the conductive fibers was characterized. Finally, a braided CNT fiber assembly was used to fabricate a prototype 2 x 2 textile touch sensor to demonstrate the performance of the sensor for smart textile applications.