Photothermal healable, stretchable, and conductive MXene composite films for efficient electromagnetic interference shielding

MXene-based electromagnetic interference (EMI) shielding nanocomposites are promising candidates to ensure the stable operation of flexible and wearable electronic devices. However, it remains a considerable challenge to develop high-performance flexible polymer/MXene composites with excellent broadband EMI shielding efficiency and healing capability. Herein, we select waterborne polyurethane (WPU) and natural rubber (NR) as the polymer matrices to fabricate flexible and healable WPU/NR/MXene composite films by forming continuous honeycomb-like conductive network using the electrostatic repulsion interaction and vacuum-assisted filtration strategy. Consequently, the WPU/NR/MXene composite films of 339 μm thick achieve an average EMI shielding performance exceeding 76.1 dB in the wide frequency range of 8.2–40.0 GHz when the MXene content is only 5.48 vol%. Compared to the WPU/NR film, the composite films show 10.3 and 8.8 times increments in tensile strength and toughness, respectively. Furthermore, the composite films can elevate their surface temperature to >114 °C under 200 mW cm−2 near-infrared light irradiation within 3 min, which can activate the PU chain segments and the hydrogen bonds between MXene and WPU to afford an interesting healable capability. Therefore, the multifunctional composite film with rapid photothermal healing property can ultimately keep its mechanical and shielding performances, and greatly extend its practical application areas.