Polypyrrole coated knitted fabric for robust wearable sensor and heater

Nowadays, there has been tremendous interest in multifunctional and smart textiles to meet the pressing demand for new and innovative applications such as personal thermal and healthcare management. Herein, we present a wearable sensor and heater by in situ polymerization of pyrrole on the knitted cellulose fabric. The knitted fabric coated with electrically conductive polypyrrole (PPy) exhibits an electrical conductivity of 303 Omega sq(-1). The PPy-cotton knitted fabric can be utilized as the strain sensor because of its high sensitivity to different motion activities. Meanwhile, the PPy-cotton knitted fabric can also act as a wearable heater due to Joule heating effect under a low voltage. Additional non-wettable treatment onto PPy-cotton fabric can efficiently improve the protection against environmental factors. The combination of stretchable knitted fabric with conductive PPy offers a low-cost and efficient solution for multifunctional wearable electronics.