Preparation and properties of waterproof and breathable cellulose acetate (CA)/polyvinylidene fluoride (PVDF) flexible electrothermal film

In this study, a method of preparing conductive film by depositing polypyrrole(PPy) on electrospun CA nanofibers is proposed. With D-CA-PPy electric heating film as the core layer, the upper and lower layers are used as its composite PVDF waterproof and breathable layers to prepare PVDF/D-CA-PPy composite electric heating film. The electric heating film is combined with the clothes through the adhesive lining. Then, the relationship between simulated body temperature and input power is tested, and the application field of the heating film is explored. The characterization results of mechanical properties and water washing resistance show that the breaking strength and elongation of PVDF/D-CA-PPy-laminated electric heating film are improved while maintaining the air permeability. PVDF film effectively prevents PPy from falling off due to water washing. After 50 times of washing, the change rate of resistance is 196%. The characterization results of electrothermal properties show that PVDF/D-CA-PPy-laminated electrothermal heating film has better thermal stability. When PVDF/D-CA-PPy-laminated electric heating film is combined with clothing, the input power reaches 7.82 W/100 cm 2 , 2.33 W/100 cm 2 and 0.92 W/100 cm 2 at ambient temperatures of – 15 °C, − 5 °C and 5 °C, respectively, and the simulated body temperature of clothing can reach 33 °C.