Programmed cryogenic fabrication of cuttlebone-inspired lightweight cellular materials with enhanced energy absorption

Lightweight engineering materials with high energy absorption are critical for various strategic fields. However, designing cellular materials that overcome the trade-off between density and energy dissipation remains challenging. Inspired by the wall-septum architecture of cuttlebone, we develop a lightweight cellular epoxy resin using a facile layer-by-layer freezing technique. The resulting material exhibits high compressive strength and specific energy absorption, reaching 34.5 J g−1 at a density of 0.55 g cm−3. The dense septa between porous wall layers in the wall-septum structure enhance structural stability against wall buckling and provide lateral confinement during compression. Such architecture also improves high-strain-rate impact strength, achieving 190% and 66% increase in dynamic specific energy absorption compared to conventional isotropic and unidirectional structures, respectively. Large-size energy-absorbing epoxy panels are readily fabricated and demonstrate impact protection performance under high-speed impact. This work provides a practical route to lightweight cellular materials with improved energy absorption efficiency. The development of lightweight engineering materials with high energy absorption capacity is critical for various strategic fields but overcoming the trade-off between density and energy dissipation performance in cellular materials remains challenging. Here the authors develop a lightweight and energy-absorbing cellular epoxy resin through a facile and scalable layer-by-layer freezing technique.