Flexible Interconnects for Electronic Textiles

Conformable electrical systems integrated in textiles offer revolutionary possibilities. Textiles constitute an obvious choice as a multifunctional electronic platform, since they are worn and used to cover many surfaces around us. The primary focus of the emerging area of electronic textiles (e‐textiles) is on developing transformative technologies to produce flexible, conformable, and large‐area textile‐based electronic systems. One of the main roadblocks to development of e‐textiles is making (fiber‐to‐fiber) interconnects within textiles, with rigid semiconductor‐based circuits and other devices, and efficiently routing these circuits. This problem is compounded by the need for the textile and other materials to withstand the stresses and strains of manufacturing and end‐use. The fundamental challenge of forming these interconnects involves making them flexible, robust, and environmentally stable while ensuring adequate electrical connectivity. From a mechanical standpoint, the transition from soft to hard materials should occur with minimum stress/strain concentration. These challenges, if unaddressed, will remain a barrier to large‐scale development of textile‐based electronic systems. This work reviews the technological issues related to the textile interconnect, providing an overview of flexible interconnects, including relevant materials, electrical and mechanical characterization techniques, ways of forming flexible conductive pathways, and potential research directions and challenges. Electronic capabilities are incorporated into textiles at various hierarchical levels, i.e., polymer, fiber, yarn, and fabric, to produce conformable e‐textile systems. One of the major challenges in e‐textiles is making (fiber‐to‐fiber) interconnects within textiles, with rigid semiconductor‐based circuits and other devices, and efficiently routing these circuits. Optimizing materials, characterization, and routing techniques are key factors in overcoming this challenge.