In-situ assembly of polypyrrole onto heterocyclic aramid for high-strength, ultratough, durable, and multifunctional films

High-strength, ultratough, multifunctional polymer-based electromagnetic interference (EMI) shielding nanocomposite films have colossal application potential in artificial intelligence, 5G communications, and flexible electronics. In this work, a large-scale, high-strength, and ultratough heterocyclic aramid@polypyrrole (HA@PPy) composite film is developed via the in-situ loading of PPy onto the HA template. The synthesized films achieve remarkable mechanical properties and high electronic conductivity by using the template effect of HA to guide the assembly of conductive polymers. When the content of PPy is 45 wt%, the HA@PPy (HP45) film possesses excellent tensile strength (240.3 MPa), significant elongation at break (25.9 %), outstanding toughness (53.1 MJ m⁻³), and exceptional folding durability owing to strong hydrogen bond interaction between PPy and HA. Furthermore, thanks to the highly connected conductive paths formed by PPy, the HP45 film exhibits satisfactory EMI shielding effectiveness (EMI SE) of 45.5 dB and specific EMI SE of 14691.6 dB cm² g⁻¹ at an ultra-thin thickness (26.3 μm). The HP45 film also demonstrates excellent electromagnetic protection, electro-/photothermal deicing, thermal therapy, and flame retardancy applications. Therefore, high-performance and multifunctional HA@PPy films have substantial potential for widespread application in EMI shielding and thermal management.