Multifunctional Ti3C2Tx MXene/montmorillonite/cellulose nanofibril films for electromagnetic interference shielding, photothermal conversion, and thermal insulation

Multifunctional electromagnetic interference (EMI) shielding composite films with thermal insulation and photothermal conversion properties are urgently needed for microelectronic devices, especially in extreme environments. Herein, flexible and thin Ti3C2Tx MXene/montmorillonite/cellulose nanofibril (MMC) composite films with the laminated brick-mud structure were prepared by vacuum filtration induced self-assembly. The MMC composite films had densely packed hierarchical structure and strong hydrogen bond interaction, which improved the mechanical strength of functional coatings (~ 127.7 MPa). Impressively, the MMC composite films had high electrical conductivity (1221.4 S m−1) and integrated excellent EMI shielding (43 dB), capable of shielding 99.99% of electromagnetic pollution. Besides, the composite films had high photothermal response and good photothermal stability, as well as also had good isotropic thermal insulation and flame-retardant properties, with low thermal conductivity (0.076 W m−1 K−1 on the plane, 0.081 W m−1 K−1 on the cross plane). Therefore, the as-prepared multifunctional composite films have promising applications in various fields such as flexible wearable devices, microelectronic devices, and human electronic equipment.