Nacre-Mimetic Graphene Oxide/Cross-Linking Agent Composite Films with Superior Mechanical Properties.

We report on the graphene oxide/cross-linking agent (GO/CA) composite inspired by the nacre structure. Based on the "brick-and-mortar" concept of nacre, graphene oxide and cross-linking agent are covalently conjugated in the form of nacre. The mechanical characteristics of the nacre-mimetic GO/CA composite film can be controlled by adjusting the preparation method, degree of cross-linking, and cross-linking times. As a result, the cross-linking strategy can drastically enhance the tensile strength (142.9 ± 6.4 MPa (~ 2.3-fold)), modulus (4.7 ± 0.36 GPa (~ 15.7-fold)), and hardness (917.4 ± 85.7 MPa (~ 9.0-fold)), which are superior to those of pristine materials. The cross-linking agent-based chemical bonding method for mechanically improved integration is mainly attributed to the formation of strong cross-linked networks between the GO-based 2D interfaces and CA. The facile fabrication process provides many opportunities to design advanced, robust, and integrated nacre-like GO/CA composites, which can be applied to future aerospace utilizations, electronic protectors, robotic elements, and permeable membranes.