A flexible and stretchable polypyrrole/knitted cotton for electrothermal heater

Electrothermal heater (ETH) is very promising in wearable electronic area for its potential thermotherapy and electrical-warming garment applications. To fabricate a suitable conductive material for wearable ETH, knitted cotton is used as substrate for in-situ polymerization of pyrrole monomers, producing conductive polypyrrole/knitted cotton fabric (PKCF) with good flexibility and stretchability. A parallel strategy for current collectors is taken to enhance the temperatures of prepared PKCF from 37.0 to 51.0 °C at 8 V. This PKCF provides a service time about 13.5 h in a continuous electrothermal process, keeping a temperature above 35 °C. Besides, the PKCF still shows good electrothermal performances after bent or stretched several thousand times, and can be sewn on fabric to realize its electrothermal function in garments, which indicates a promising wearable market.