Aromatic phase change microspheres constructed nanocomposite films for fluorine-free self-cleaning, absorption-dominated EMI shielding, and high-temperature thermal camouflage

The combination of high shielding effectiveness and excellent thermal insulation is highly attractive for electromagnetic interference (EMI) shielding materials, yet remains challenging in the absence of thermal stability and self-cleaning effect. Here, poly(arylene ether nitrile) (PEN), an aromatic super engineering polymer, is synthesized and one-step self-assembled into phase-changeable microspheres in an oil-in-water microemulsion system, synchronously settling thermal lability and leakproof of conventional phase change materials. Prefunctionalized multi-wall carbon nanotubes are subsequently immobilized on PEN-based phase change microspheres for EMI shielding and thermal camouflage compartments. The resultant compartments are integrated into macroscopical nanocomposite films with segregated structures via hot-compressing densification. Due to the 3D interconnected cavities, the shielding effectiveness of the PEN-based nanocomposite film is strikingly up to 43 dB with an excellent absorption coefficient of 0.99. Meanwhile, the nanocomposite film exhibits outstanding thermal camouflage throughout a wide temperature range of 80-200 degree celsius at a low thickness of similar to 1.5 mm. Interestingly, superb fluorine-free self-cleaning is endowed with its inherent hydrophobic surface (contact angle up to 148.6 degrees) overlaid with micropapillaes. Our work sheds light on such application integration of fluorine-free selfcleaning, absorption-dominated EMI shielding, and high-temperature thermal camouflage.