In silicon testing of the mechanical properties of graphene oxide-silk nanocomposites

Graphene oxide (GO)-based nanocomposites have attracted increasing attention due to its intriguing mechanical and electrical properties. In this work, we studied the mechanical properties of the GO-Silk nanocomposites focusing on the interactions between GO sheets and silk fibroins using molecular dynamics simulations. We found that the oxygen content in GO sheets significantly influences the mechanical properties of a GO-Silk nanocomposite, because the oxygen plays a crucial role in hydrogen bonds (H-bonds) formation at the GO sheets–silk interface. Water content also plays important roles in the mechanical properties of the composites. Particularly, we find that there is an optimal water content for a best mechanical performance of the nanocomposite. When the water content is low, water molecules can help to form H-bonds between GO sheets and silk, and thus stabilizes the H-bond network at the interface and enhances the mechanical performances of the nanocomposite. However, when the water content is too high, a water layer forms and acts as a lubricant at the interface, which reduces the strength of the composite. This study may provide guidelines for the design of a GO-Silk nanocomposite with superior mechanical performance.