Microscopic exploration of interfacial and wetting properties of graphene/silica heterostructures

Graphene/silica heterostructures have shown potential applications in broad fields, in which achieving well-defined composite structures is essential for optimizing non-crystalline composite properties and enabling new applications. However, the interfacial structures and properties of graphene/silica and the associated functions of underlying amorphous surfaces are not thoroughly understood yet. Herein, molecular simulations were performed to systematically investigate the adhesion, detachment, and wettability of graphene on amorphous silica surfaces. We simulated and constructed actual materials-oriented amorphous silica substrates with controlled morphology. It is demonstrated that graphene on amorphous silica surfaces exhibits three distinct contact states: suspended, partially conformal, and highly conformal. It is remarkable to show extremely low adhesion strength for graphene suspended on silica surfaces. The influence of different contact modes on the graphene/silica wettability was fully revealed for the first time. Grand Canonical Monte Carlo simulations were conducted to generate adsorbed water layers on the hybrid graphene/silica structures. The interfacial behavior of graphene/silica was also disclosed under humidity conditions, and meanwhile, the dynamic process of water inserting into the hybrid interlayer was captured. Overall, our simulations provide insight into tuning the morphology and wettability of graphene through substrate patterning, potentially paving the way for the design and application of graphene/silica heterostructures.