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compatibility with the skin in many circumstances, in flexible printed electronic devices such as clothing. These stretchable electronic inks deliver large areas. The conductive tracks are produced in a
are damaged when washed and are uncomfortable transistors and oscillators. Apart from the obvious stable performance despite repeated elongation. four-step process and one of these can be patterned
to wear because they are not breathable. Wearable, requirements of conductivity, fine line resolution, A third-party evaluation of fabrics that incorporate using an inkjet printer.
textiles-based electronics present new possibilities adhesion and flexibility, the new applications require these DuPont materials to create thin electronic
for flexible circuits, healthcare and environment stretchability, washability and formability, Silver circuits have shown them to be washable, durable, Inkjet printing of graphene-based conductive inks is
monitoring, energy conversion, and many others. nanoparticles (NPs) as inkjet printing inks are the and capable of withstanding up to 100 wash cycles. an encouraging research approach in the field of
Electronic textiles (e-Textiles) are innovative textile most reported and utilised conductive inks because These DuPont materials can be used in many printed electronics as both the benefits of inkjet
materials, (fabrics, yarns and threads), that of their excellent electrical conductivity and strong common manufacturing processes to produce smart printing and extraordinary electronic, optical and
incorporate conductive fibres or elements directly antioxidant characteristics. However higher clothing, including fitness and outerwear, without mechanical properties of graphene can be exploited
in/on to the textile substrate. These materials concentration of NPs and higher sintering significant investment. and has recently been an active field of research.
eliminate wires and hard electronics, and the temperatures are required in order to obtain
resultant products are soft and tactile. Current continuous metallic phase, which increase
technologies include weaving of separate metal processing cost and limit the choice of substrates to

Inkjet printing
threads into the textile, printing/deposition of be printed because of their heat sensitivity.
conductive polymers, printing metallic inks on to the Conductive inks are useful for a range of
surface, plasma deposition on the threads and applications, including printed and flexible electronics Crucially, smart fabrics will require devices to be Graphene is carbon in the form of single-atom-thick
Industry data shows that after a decade of advances development of the printed electronics industry. electroless plating. such as radio frequency identification (RFID) connected, much like with a PCB. National Physics membranes, and is highly conductive. The
in digital printing technologies for textile, only 2% of They’re new and novel, and the business antennas, transistors or photovoltaic cells. The Laboratory UK developed a new method for graphene-based inks can be applied onto cotton to
the world’s printed textiles are produced digitally. opportunities they present are growing exponentially. Inkjet printing is one of the most promising advent of the internet of things is predicted to lead to producing conductive textiles which could end up produce a conductive textile. The work, published in
Most of digital printing on textiles is done today techniques for the fabrication of wearable electronics new connectivity within everyday objects, including in turning a fabric into, effectively, a wearable PCB, the journal Carbon, demonstrates a wearable motion
mainly on polyester fabrics using dye sublimation. Recent advances, such as embroidering circuits into due to number of advantages over conventional food packaging. Thus, there is a clear need for connecting all the active parts of the wearable. It can sensor based on the conductive cotton. The
e-Textiles or smart garments, smart clothing, fabric or transparent sensor material that can be manufacturing techniques such as digital and cheap and efficient production of electronic devices, be applied to almost all woven and knitted fabrics. adhesion of the modified graphene to the cotton
electronic textiles, smart textiles, or smart fabrics; printed on to textiles, are helping to create a range of additive patterning, reduction in material waste, using stable, conductive and non-toxic components. This technique could make the integration of fibre is similar to the way cotton holds coloured dyes,
have a digital component or electronics embedded technologies that bring together the clothing, deposition of controlled amount of materials and These inks can also be used to create novel electronics simple and practical by enabling and allows the fabric to remain conductive after
within them. While it may still be in its infancy, it is a technology and textile industries to create fabrics compatibility with various substrates. The composites, coatings and energy storage devices. In lightweight circuits to be printed directly onto several washes.
fast-growing market with new capabilities being with capabilities for users as varied as athletes, requirement of conductive inks can be divided into the past, DuPont Microcircuit Materials (DuPont) complete garments. The methodology binds,
developed that will enable users to interact with their patients, soldiers and ordinary consumers. Most of two categories based on their use. First, there are introduced a suite of stretchable electronic ink chemically, a catalyst to the fibre – a nanometal seed The printing, especially digital printing, of conductive
surroundings and to communicate data via the current wearable technologies rely on rigid transparent conductive inks for applications such as materials for use in smart clothing applications and layer, and can be applied at any stage of the inks on to textile substrate is an active research area
embedded sensors or conductive yarn through the electronic components mounted on flexible materials replacement of indium tin oxide, photonic and optical other wearable electronics. The materials provide an manufacturing process. It is highly conductive, and has the potential to revolutionise the e-Textiles
clothes they wear. e-Textiles are impacting the such as plastic films or textiles. These offer limited devices, display, solar cells, and touchscreens. elegant, manufacturing-ready alternative to many provides excellent flexibility and can be used on arena and can offer a multitude of opportunities for
Second, there are conductive inks for interconnects traditional methods of embedding electronics in smart clothing and flexible electronics applications.

October/November 2017