Electronic Circuits Integration in Textiles for Data Processing in Wearable Technologies

To become an integral part of the everyday outfits, wearable electronics are expected to be lightweight, conformable, imperceptible for the user and life‐proof. The prospect of integrating modern technologies in clothes requires electronic circuits in textiles which are able to perform complex computing with high reliability. Four approaches to smart textile fabrication are described in this review: textile circuits, functionalized fibers, flexible circuits, and hybrid stretchable circuits. In the first two, fabric serves as a substrate for the electronic circuit to maintain essential textile properties. In basic textile circuits, standard electronic components directly attached to fiber tracks insure elementary electronic functionalities while remaining a noninvasive solution. Then, functionalized fibers replace the rigid electronic parts, to make the electronics even more integrated, merging inside the core of the fiber. These most recent works are today limited to basic logic circuitry and quasi‐static applications. The third and fourth approaches have shown the advantages to rely on well‐established technologies with dedicated flexible/stretchable hybrid substrates processed separately from the garment. Despite a loss in wearing comfort, this axis of research is driven by the superior computational performances. Heterogeneous integration in textile for wearable technologies is reviewed. Different approaches to smart textile fabrication are described at three levels: garment, fabric, and fiber. The advantages and drawbacks of the various technologies are discussed in terms of functional performances and use. Latest progresses in integration through the fabrication of complex devices based on the fiber functionalization are also highlighted.