Hydrophobic Interaction‐Directed Solvent‐Free Ambient‐Pressure‐Dried MXene Aerogels

ABSTRACT Scalable solvent‐free ambient‐pressure drying (APD) of robust multifunctional MXene aerogels remains significantly challenging. We present a hydrophobic interaction‐directed assembly strategy among MXene, chitosan (CS), and glutaraldehyde (GA) to engineer aerogels with programmable hydrophobicity‐mechanics. Selective reduction of CS amine groups suppresses capillary forces upon solvent‐free APD, yielding 4,477% compressive strength enhancement over conventional MXene aerogels. Composition tuning delivers switchable electromagnetic functionality: 25.6 wt.% CS generates a 76 dB microwave shielding effectiveness, while 67.4 wt.% yields a 6.4 GHz broadband microwave absorption, which is comparable to the best MXene aerogels. The APD MXene aerogels further exhibit exceptional thermal protection, characterized by a record‐high limiting oxygen index of 60%, outstanding thermal insulation, reliable structural integrity at elevated temperatures, and a high‐efficiency early fire‐warning capability, outperforming previously reported nanostructured monoliths. This work offers a general, scalable, and solvent‐free route for assembling MXene and other nonstructured aerogels with integrated mechanics and functionalities, advancing their application in aerospace and energy systems.