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

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/Al2O3) stratified films inspired by the hard-soft-hard architecture of the scaly-foot snail shell. Amorphous Al2O3 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.