Scaly‐Foot‐Snail‐Inspired Ultralight Carbon Nanotube/Alumina Stratified Films for High‐Rate Impact Protection and Optical‐Thermal‐Electromagnetic Multifunctionality

ABSTRACT Lightweight protective materials for complex environments must combine high‐rate impact resistance with optical, thermal, and electromagnetic functions, yet conventional multilayers often add weight without effective interfacial coupling. Here, we report interfacially bonded carbon nanotube film/amorphous alumina (CNTF/Al 2 O 3 ) stratified films inspired by the hard‐soft‐hard architecture of the scaly‐foot snail shell. Amorphous Al 2 O 3 layers are deposited on ultralight CNTF to form asymmetric and symmetric rigid‐flexible configurations with possible chemically coupled Al‐O‐C interfaces. Under laser‐induced microparticle impact, the hard‐soft‐hard film achieves a specific energy absorption of 5.24 ± 0.21 MJ kg −1 at approximately 320 m s −1 . Post‐impact microscopy suggests that ceramic fragmentation, carbon nanotube network deformation, and interfacial pull‐out or fracture contribute to energy dissipation. A possible contribution from layer‐dependent load redistribution is proposed. The same architecture also produces dye‐free structural colors, rapid tunable Joule heating, and stable X‐band electromagnetic interference shielding of 38–45 dB. This biomimetic design offers a lightweight platform for impact‐resistant, optically camouflaged, multifunctional personal protection.