Preparation and Characterization of PU/PDA/PPy Flexible Composite Film for Electric Heating

Polypyrrole (PPy) is one of the most widely researched conductive polymers due to its high electrical conductivity, good thermal and environmental stability, oxygen resistance, heterocyclic structure, non-toxicity, and simple synthesis method, and is an excellent candidate for electric heating materials. For better application in textile heating, a polyurethane (PU) film is used as a substrate and dopamine (PDA) is used as a multifunctional platform for the secondary reaction on the film to immobilize the polypyrrole on the surface of the film, making it a smart wearable element. By varying the amount of PPy to control its direct oxidative polymerization reaction, materials with good electrical conductivity and flexibility were obtained. It has a fast electrothermal response at low operating voltages (up to 118 °C after 20 s at 5 V), good flexibility, light weight and uniform heat distribution. It has significant advantages compared to other electrical heating materials.