Seamless electronics give smart textiles a push
“Electronics seamlessly integrated into fabrics represent the ultimate form of smart textiles.” It is this belief that led Monica Craciun, Professor of Nanoscience and Nanotechnology at the University of Exeter, to kick start the E-TEX (All-organic devices in textiles for wearable electronics) project in 2016. According to her, market success requires soft, safe, stylish, comfortable and colourful fabrics that discreetly and unobtrusively include a whole host of additional functionalities. Such a 'smart' offering could easily find a prominent place in markets like clothing, home fabrics, automotive textiles, medical appliances, and much more. Currently, however, the growth of the smart textile market is hindered by the use of rigid devices or flexible ones with poor performance. As Prof. Craciun puts it, “all these technologies are based on components glued onto fabric, which defies the ambition for a mechanically flexible and low-weight technology needed to preserve the properties of the textiles we are used to and want to wear.” The solution could arise from groundbreaking advances in atomically thin materials, and more specifically graphene. Its flexibility, high electrical conductivity, optical transparency, thermal stability and ease of processing into different structures indeed make it an excellent candidate for a new generation of smart textiles. “We have embarked on exploring the uncharted territory of woven smart textiles made of intertwined graphene-enabled electronic fibres,” Prof. Craciun explains. “We decided to focus on two types of electronic fibres: capacitive touch-sensors and light-emitting devices. With our solutions, an information display could be used on clothes to change their colour for security alerts, or medicine alerts to provide assistance to children or senior people. More complex displays combined with communication technology could lead to textile GPS, phones and monitors that show and govern the usage of drug implants. We can even think of applications in the fields of security and energy harvesting.” To allow for compliant and robust contact between the devices and the textiles, the former must bend and stretch to accommodate strains. With its atom-thick carbon layer, graphene fits the bill, and its biocompatibility further facilitates its application to smart textiles. Graphene fused with PP fibres Although not yet completed, E-TEX has successfully developed electronic fibres with functional devices based on graphene, directly fabricated on polypropylene (PP) textile fibres. PP fibres are ubiquitous in textile for applications ranging from healthcare, security and defence to daily life clothing and fabric. This is due to their lightness, low thermal conductivity and high stain resistance, and also to how they exhibit extreme mechanical flexibility at low temperature and resistance to bacteria. All this, whilst being recyclable and ecologically friendly. To maintain PP fibres’ characteristics, the team came up with a method to make insulating PP fibres conductive, by coating them with atomically-thin graphene, as well as a non-invasive manufacturing process for the fabrication of electronic functions on PP fibres that’s compatible with industrial processes. “We have achieved graphene electronic fibres with touch-sensing and light-emitting functionalities. By creating woven arrays from such fibres, we could demonstrate pixels with different sizes that can be integrated in future textile displays and devices for position sensitive measurements,” Prof. Craciun enthuses. This breakthrough has already piqued the interest of industry. CenTexBel, the scientific and technical centre for the Belgian textile industry, sees “potential for a disruptive technology with a wide array of potential new applications.” Until then, the team will aim to demonstrate other types of electronics integrated in textiles, notably small and discrete audio earphones and microphones using graphene electronics to generate sound waves.
Keywords
E-TEX, smart textiles, graphene, fabrics, seamless, touch sensors, light-emitting, PP fibre
