Printed fabric heater based on Ag nanowire/carbon nanotube composites

The increasing demand for smart fabrics has inspired extensive research in the field of nanomaterial-based wearable heaters. However, existing stretchable heaters employ polymer substrates, and hence require additional substrate-fabric bonding that can result in high thermal contact resistance. Moreover, currently used stretchable fabric heaters suffer from high sheet resistance and require complex fabrication processes. In addition, conventional fabrication methods do not allow for patternability, thus hindering the fabrication of wearable heaters with diverse designs. Herein, we propose an improved spray coating method well suited for the preparation of patternable heaters on commercial fabrics, combining the structural stability of carbon nanotubes with the high electrical conductivity of Ag nanowires to fabricate a stretchable fabric heater with excellent mechanical (stretchability approximate to 50%) and electrical (sheet resistance 22 Omega sq(-1)) properties. The fabricated wearable heater reaches typical operating temperatures of 35 degrees C-55 degrees C at a low driving voltage of 3-5 V with a proper surface power density of 26.6-72.2 mW cm(-2) (heater area: 3 cm x 3 cm) and maintains a stable heating temperature for more than 30 h. This heater shows a stable performance even when folded or rolled, thus being well suited for the practical wearable applications.