Maximum utilization of nacre-mimetic composites by architecture manipulation and interface modification towards critical damage state

Diverse ultrahigh-strength platelets offer immense promise for high-efficient energy-absorbing design of nacre-mimetic composites. Yet, incompatible interfacial bonding has greatly restricted the pull-out toughening efficiency to a superior level, resulting in insufficient utilization of platelet strength advantages. Herein, we demonstrate an ingenious critical damage state (CDS) control method to utterly exert the energy absorption potential of nacre-mimetics by pursuing the most efficient toughening mode, which is a universal maximum utilization strategy applicable to platelets with arbitrary strengths. Architecture manipulation results suggest that small aspect ratio platelets can generate superb toughness amplification, and stiffening effect is favored for large-size platelets with dense content and high offset ratio, which is consistent with experimental results. More importantly, by identifying the upper limit of shear strength and the lower limit of plastic deformability, we elucidate the interface modification principle imposed on optimized structure to achieve perfect compatibility. Interestingly, we find the uniform staggered pattern is more recommended for superior energy-absorbing design owing to its pronounced strengthening-toughening effect and looser compatibility restriction compared with the random staggered pattern. Furthermore, the proposed CDS control method should not only be generally feasible for nacre-mimetics, but also shed light on other hard/soft layered composite designs targeting utmost synergistic toughening.