Shell-mimetic (PE/TiO 2 ) 4 nanolayered composites stacked alternatively by 20 nm-thick PE layers and 55 nm-thick nanocrystalline TiO 2 layers are synthesized by a combination of the layer-by-layer self-assembly and the chemical bath deposition methods. The critical cracking strain and the apparent fracture energy of the bio-mimetic nanolayered composites are determined as 0.56% and 0.98 J m À2 , respectively, by the simply supported beam bending testing. Fatigue properties of the (PE/TiO 2 ) 4 nanolayered composites are evaluated by the dynamic bending testing method. The critical fatigue strain amplitude corresponding to the lowest strain amplitude for fatigue cracking of the present (PE/TiO 2 ) 4 NLCs is 0.0853%, which is much lower than the critical cracking strain (0.56%) under monotonic bending. The finding indicates that the potential fatigue threat to the long-term reliability of the bio-mimetic nanolayered composites needs to be concerned.