Layer-by-layer self-assembled MoS₂/CNTs/CA coated TPU composite film for synergistically enhanced EMI shielding and dual-thermal deicing

This work presents a multifunctional composite film with integrated photothermal and electrothermal conversion, electromagnetic interference (EMI) shielding, and active de-icing capabilities, fabricated via electrospinning combined with layer-by-layer (LbL) self-assembly. Polydopamine (PDA)-modified thermoplastic polyurethane nanofiber membranes (PDA@TPU) served as the substrate. Synergistic interaction with sodium alginate (SA) enabled the layer-by-layer self-assembly of molybdenum disulfide (MoS₂) and carbon nanotubes (CNTs) onto the substrate surface. Subsequent Ca²⁺drop-addition reaction cross-linking ultimately formed a robust and stable coating. The PDA and SA layers significantly enhance interfacial adhesion between the conductive fillers (MoS₂/CNTs) and the polymer matrix, ensuring mechanical durability and efficient thermal conversion. The resulting five-layer film exhibits excellent performance: a photothermal temperature rise of 69.2 °C under 1 sun irradiation (100 mW/cm²), electrothermal heating exceeding 80 °C at 7 V, and an EMI shielding effectiveness of 33.8 dB in the X-band. Notably, this film exhibits outstanding durability, with its electrical conductivity remaining virtually unchanged after repeated washing. Under dual photothermal and electrothermal stimulation (1 sun +7 V), the film can completely melt surface ice within 60 s, effectively preventing electromagnetic shielding efficiency degradation caused by ice accumulation. The layer-by-layer self-assembly technique based on PDA and SA systems offers a novel strategy for fabricating multifunctional composite films with outstanding comprehensive properties, demonstrating broad application prospects.