Ultralong Carbon Nanotube Yarns Integrated as Electronic Functional Elements in Smart Textiles

The field of smart textiles is increasingly growing, producing a variety of new textile materials and fabric functionalities. Yet, significant challenges in areas such as washing, durability, electronic interfacing, and sustainability prevail. To gain widespread adoption, electronically integrated garments will need to rely on robust, fully integrated, and lightweight fiber-based conductive systems. In this paper, we propose the use of Ultralong Carbon Nanotube (UCNT) yarns, as a potential solution to some of the challenges mentioned above. In UCNT, the fibers’ ratio between width and length is orders of magnitude larger than typical carbon nanotube fibers. Amongst other advantages, this enables the manufacturing of stable, workable yarns, made of a network of twisted fibers (tows), which are suitable for integration in fabrics. Our research includes the creation of textile prototype demonstrators integrated with UCNT yarns, which were tested under military-grade textile standards for both mechanical durability and electric functionality. The demonstrators were surveyed before, during and after the various tests, including washability, abrasion, and weathering. The results provide some encouraging results, especially in instances where the UCNT yarns were enhanced by a polymer coating, which provided improved mechanical properties and electrical durability. After washing, tests of the washing residue revealed the presence of UCNT nanofibers, which are banned by the World Health Organization. The paper discusses the possible source of the nanofibers in the washing residue and proposes future improvements to the coating and the testing method. A detailed account of the prototype demonstrators is provided including the weaving pattern, the electronic circuitry, and the component configuration, which enables functionalities of heating, haptic alert, fabric tear detection, touch sensing and moisture detection.