Smart textiles: e-textiles – Integration and constraints

Intelligent textiles and their sub-assemblies, or e-textiles, first appeared at the end of the 20th century, mainly thanks to the chemical and electronics industries, which made it possible to functionalize fibers and textile structures. These are complex systems whose design and manufacture require specific skills in well-defined fields. In concrete terms, this means mastering the design and manufacture of rigid and flexible electronic circuits, the operation of sensors and actuators, and the ability to integrate them into flexible structures. The ability to program microcontroller boards such as ARDUINO or LILIPAD is also imperative. In addition, skills are required in the design and manufacture of textile structures using spinning, dyeing, coating, weaving, knitting, braiding, embroidery and other techniques.

These intelligent textile systems combine structures from the textile sector with devices and circuits from the electronics industry. These two sectors (textiles and electronics) differ considerably in terms of morphological and mechanical properties, as well as resistance to washing, cleaning, maintenance, etc. This calls for a special approach to the design phase of smart textiles and the integration of miniaturized electronic devices. This calls for a special approach to the design phase of intelligent textiles and the integration of miniaturized, flexible electronic devices, or even purely textile components without rigid elements. The general theoretical basis for the design of intelligent textile systems is presented in the form of Human-Physical-Cybersocial Systems.

Design must take into account the very different mechanical properties of textiles and electronic devices. These differences pose problems, for example, when it comes to connections between the flexible conductive tracks and the rigid conductive parts of electronic components. To avoid breakages and failures due to poor contact, interfaces based on flexible PCBs (printed circuit boards) in Kapton or PET are used; it is then possible to sew or embroider with electrically conductive threads while soldering the rigid "legs" of microcontrollers, resistors, LEDs, etc. Conductive adhesives can also be used to make electrical connections between flexible textile conductors and the rigid parts of "conventional" electronic components.

The miniaturization of electronic components has made it possible to integrate them into the heart of garments. These textile structures are now capable of measuring environmental and/or physiological parameters, then analyzing them to provide an adapted response or take appropriate action. The production of e-textile sensors used to measure physiological parameters calls on well-known textile manufacturing techniques that can be easily transferred...