Transient Thin-film Zinc Based Sensor on Flexible Nettle-Gelatin Coated Fabric

In the last years, the manufacturing of smart textile (e-textile) has been showing outstanding achievements in the fabrication of electronic systems, thanks to their exceptional electrical, thermal and optical properties. However, material performance and sustainability, complex integration methods and limited end-of-life processability are major challenges to wide adoption of e-textiles. In this work, a commercial 100% Nettle-based fabric coated with a Gelatin-glycerol resin, acting as planaritazion layer, was used for the first time as a substrate for the fabrication of thin-film temperature sensors. The devices were tested and characterized over a temperature range from 25 °C to 60 °C (at relative humidity of 26 ± 3%), showing a temperature coefficient of resistance α of 2.3×10-3 °C-1. Device functionality was demonstrated down to 2mm bending radius. In addition, the temperature sensor showed degradation properties, since natural dissolution occurred within 10 days, while it took 14 days for the planarization layer to degrade in De-Ionized (DI) water. The development of this device represents the first demonstration of a sustainable and fully-green technology for the fabrication of thin-film temperature sensors directly on nature-based fabrics, with possible application in recyclable wearable electronics and human health monitoring.