Robust biomimetic Ti₃C₂T_x nanocomposite films enhanced by mussel-inspired polymer for highly efficient electromagnetic shielding and thermal camouflage

Ti₃C₂T_x has shown significant applications in many fields, such as electromagnetic interference (EMI) shielding and thermal camouflage. Yet, the preparation of high strength and functional Ti₃C₂T_x film is still challenging due to its weak interlayer interactions. Herein, we carefully design and synthesize a series of water-soluble polyacrylate polymers with different catechol group contents inspired by mussel byssus. Then, we assemble them with Ti₃C₂T_x by facile colloidal self-assembly approach, finally achieving robust and multifunctional Ti₃C₂T_x nanocomposite films through a nacre-mimetic construction strategy. These polymers combined with the Ti₃C₂T_x through hydrogen and coordination bonds, thus effectively enhancing the interfacial interactions of the nacre-mimetic films, resulting in the strength and toughness being enhanced to 4.5 and 4.4 times that of pure Ti₃C₂T_x film, respectively. Furthermore, the conductivities and EMI shielding efficiencies can be significantly improved by increasing the content of catechol groups in the polymers. Notably, we report for the first time that the ultrathin Ti₃C₂T_x nanocomposite films possess very low infrared emissivity (<0.2) and excellent infrared stealth performance, which can camouflage a high temperature surface of 100 °C to 33.8 °C. This biomimetic material design idea undoubtedly opens up a new path for constructing robust and multifunctional composite materials.