2, University of Manchester, Manchester, , United Kingdom
There have been growing interests in multi-functional wearable electronic textiles (e-textiles) due to their potential applications in sportswear, military uniforms, environmental monitoring and health care. Currently, metal inks based on Ag, Cu or Au are most commonly used materials due to their higher electrical conductivity. However, metal inks are very expensive, toxic and not-biocompatible; oxidise rapidly and require higher sintering temperature. Graphene, a single atom thick two-dimensional closely packed honeycomb lattice of sp2 carbon allotropes, is considered to be one of the most promising materials for fabricating flexible wearable electronics due to its unique physical and chemical properties such as large surface area, record thermal conductivity, excellent mechanical strength and superior electronic mobility. In addition, graphene-based inks such as reduced graphene-oxide (rGO) can produce durable, washable and potentially more environmental friendly e-textiles due to the hydrogen bonding between hydroxyl groups in cotton and residual oxygen containing groups in reduced graphene oxide (rGO). Recent studies have shown promise for fabricating next generation graphene-based e-textiles. However, these are based on time and materials consuming multiple dip and dry or vacuum filtration techniques, graphene/metal composite inks, higher post reduction temperature and the use of toxic reducing agents such as hydriodic acid, sodium borohydride and hydrazine. Here we report a simple, scalable and environmental friendly process of manufacturing next generation multi-functional graphene-based wearable e-textiles. We use a simple pad dry technique to produce graphene-based conductive textiles, which could potentially produce textiles at very high commercial production rate (150 m/min). The graphene e-textiles thus produced are durable, washable and flexible with enhanced tensile properties. We demonstrate multifunctional uses of these graphene e-textiles such as flexible supercapacitors, heating elements and various sensors.