Hydrogel-induced ANF-MXene-PEDOT:PSS film by ultra-fast protonation for electromagnetic interference shielding

The development of a multifunctional conductive film to meet the requirements of flexibility, high-strength and exceptional electromagnetic interference (EMI) shielding capacity in the electronic devices has attracted extensive attention. A strategy of hydrogel-induced ultra-fast protonation was proposed for preparing aramid nanofibers-transition metal carbonitrides-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (ANF-MXene-PEDOT:PSS) conductive films. The ultra-fast protonation process would induce the formation of ultra-long molecular chains and the reconstruction of cross-linking networks to enhance the mechanical properties of films. The ultimate tensile strength of ANF-MXene-PEDOT:PSS (60%) film reached 233.6 MPa, showing an increase of 189.5%. Meanwhile, the encapsulation of conductive PEDOT:PSS layer effectively addressed the issues of the brittleness and highly oxidization susceptibility of MXene. The EMI shielding effectiveness of ANF-MXene-PEDOT:PSS (60%) film reached 45.7–48.2 dB from 8.2 to 26.7 GHz at a thickness of 36 μm. After a month for exposing to air, the EMI shielding capability of ANF-MXene-PEDOT:PSS (60%) film still remained stable (> 42.5 dB). This hybrid film also exhibited high conductivity (264.7 S·cm⁻¹), self-cleaning, fire retardancy and joule heating properties, which was as an intelligent sensor to realize the real-time monitoring of human physiological signals. This work paves the way for large-scale production of next-generation high-performance EMI shielding films, demonstrating huge potential in electromagnetic protection, thermal management and intelligent wearable devices.