Lightweight, multifunctional MXene/sodium alginate film with ordered porous structure for broadband electromagnetic...

Lightweight and multifunctional aerogel films have emerged as promising candidates for electromagnetic interference (EMI) shielding and infrared (IR) stealth. However, current pore structures are mostly random, and achieving the construction of oriented porous layer structures remains a challenge. Herein, the MXene/sodium alginate (SA) films with ordered porous structure are fabricated via long-channel wet spinning combined with confined freeze-drying. The slit channels generate a stable shear field that induces ordered alignment of MXene nanosheets, while Ca²⁺-triggered ionic crosslinking of SA and interfacial coupling with MXene ensure robust structural stability. Confined freeze-drying further creates interlayer pore channels without disrupting the layered orientation. This oriented porous architecture prolongs electromagnetic wave dissipation pathways and reduces effective thermal conductivity, enabling simultaneous EMI shielding and IR stealth enhancement. When the content of MXene is only 50 wt%, the aerogel films achieve an EMI shielding efficiency of 65 dB across X, Ku, and K bands, alongside a low thermal radiation temperature of 76.87 °C under a 150 °C background. Additionally, favorable Joule heating and photothermal conversion capabilities are demonstrated, highlighting potential for personal protection and multi-scenario applications. This work offers a scalable strategy for designing oriented porous structures toward integrated EMI shielding and IR camouflage materials.