Well-aligned MXene/chitosan films with humidity response for high-performance electromagnetic interference shielding.

MXene/polymer composites have been used as electromagnetic interference (EMI) shielding materials due to metallic conductivity of MXene recently. Considering the biodegradability, nontoxic effects and renewable nature of biomass polymer, chitosan (CS)/MXene films with an EMI shielding function were prepared by vacuum assisted filtration. The well-aligned Ti3C2Tx layers endow CS/MXene films with excellent electrical conductivity, which is association with air humidity, and EMI shielding property. The 37-micron-thick CS/MXene film at a T3C2Tx content of 75 % exhibits a high EMI shielding effectiveness of ∼ 34.7 ± 0.2 dB due to the excellent electrical conductivity of CS/MXene films (∼ 1402 ± 70 S m-1) and multiple internal reflections of Ti3C2Tx flakes. Moreover, the specific shielding effectiveness of 13-micron-thick CS/MXene film at a T3C2Tx content of 50 % reaches to 15153.9 ± 153 dB cm-1, outperforming the reported biomass-based EMI shielding composites in the X-band frequency. Due to these advantages, the film shows potential applications in the next-generation EMI shielding materials.