Electronic textiles (e-textiles) are being viewed as a revolutionary material for a variety of industries, including healthcare. Currently, wearable electronics rely on rare and sometimes toxic materials that contribute to the build-up of e-waste. To make these devices sustainable, they must be made out of renewable materials.
The team created a thread made of conductive cellulose. Cellulose thread has major potential for electronics textiles and it can be used in many ways. This thread could be used to create garments with built-in electronic smart functions made out of non-toxic, renewable and natural materials. The cellulose fiber used is of Ioncell® type.
The cellulose thread is made conductive by dyeing it with electrically conductive polymeric materials. Measurements show that the dyeing process gives cellulose thread a record high conductivity that can be increased further with silver nanowires. The team created the electrically conductive yarn in a layer-on-layer coating process with ink based on a biocompatible polymer. The e-textile thread has record-high conductivity for cellulose thread, in relation to volume. The conductivity of the biocompatible polymer-coated thread was maintained after five washes.
Researchers sewed the electrically conductive cellulose threads into a fabric with a standard household sewing machine. This created a thermoelectric textile that produces small amounts of electricity when heated on one side, for example when pressed against skin. At 37° C, the textile can generate 0.2 microwatts of electricity.
The e-textiles could be used in healthcare to regulate, monitor and measure various health metrics and could find other applications in the textile industry to limit the amount of waste produced. Natural materials and fibers have become increasingly common as a replacement for synthetics. Cellulose has sustainable extraction and can be recycled.