Nacreous aramid-mica bulk materials with excellent mechanical properties and environmental stability

Low density, high strength and toughness, together with good environmental stability are always desirable but hardly to achieve simultaneously for man-made structural materials. Replicating the design motifs of natural nacre clearly provides one promising route to obtain such kind of materials, but fundamental challenges remain. Herein, by choosing aramid nanofibers and mica microplatelets as building blocks, we produce a nacreous aramid-mica bulk material with a favorable combination of low density (∼1.7 g cm^-3), high strength (∼387 MPa) and toughness (∼14.3 MPa m^1/2), and impressive mechanical stability in some harsh environments, including acid/alkali solutions, strong ultraviolet radiation, boiling water, and liquid nitrogen, standing out from previously reported biomimetic bulk composites. Moreover, the obtained material outperforms other bulk nacre-mimetics and most engineering structural materials in terms of its specific strength (227 MPa/[Mg m^-3]) and specific toughness (8.4 MPa m^1/2/[Mg m^-3]), making it a new promising engineering structural material for different technical fields.