Strain sensing fabric integrated with carbon nanotube yarn for wearable applications

Textiles, as a desired platform for wearable smart technology, can be integrated with smart elements in the hierarchical levels of the fabric structure. In this study, a new way to make strain sensing fabric was developed by embedding a single strain sensing carbon nanotube (CNT)-based yarn into the woven structure. To overcome the abrasion during insertion, the yarn was coated with poly(vinyl alcohol) (PVA) to achieve higher mechanical performance. The gauge factor of the yarn was improved from 0.91 to 1.64. The sensing properties of CNT/PVA yarn integrated strain sensing fabric showed a gauge factor of over 1.1, a degree of linearity of more than 97% and good stability and repeatability during cyclic loading. Fabric with different integrated yarn lengths, patterns and output connections has also been investigated. The results showed that the yarn length and bend over section had a great influence on the strain sensing properties of the fabric. Furthermore, the fabric strain sensor exhibited a quick and precise response to the finger motion detection, demonstrating potential in wearable electronics.