A flexible film is designed as a multifunctional sensor with high electrical conductivity, rapid electrothermal response, and high strain sensitivity. Abstract Herein, a flexible film, called PPA film, is designed as a multifunctional sensor with high electrical conductivity, rapid electrothermal response, and high strain sensitivity. The film contains polyvinyl alcohol (PVA), graphene nanosheets (GNs), nanocellulose crystals (CNCs), polydopamine (PDA), and silver nanoparticles (Ag NPs), symbolized as PPA film. The CNCs enhance the dispersion o...