Effect of surface grafting on the oil–water mixture passing through a nanoslit: a molecular dynamics simulation study

Graphene oxide-based membranes hold great promise in composite materials for applications such as wastewater treatment and oil–water separation. In this study, classical molecular dynamics simulations were employed to investigate the separation of water from an oil–water mixture using a two-layer graphene oxide membrane. The effects of random and stripe-like grafting patterns on penetration efficiency were explored, focusing on varying grafting densities. The results show that increasing grafting density reduces permeability of both oil and water molecules, highlighting the critical role of surface functionalization in membrane design. Notably, the stripe grafting pattern significantly enhances penetration efficiency by optimizing steric interactions around the nanoslit. These findings contribute to the development of nanocomposite materials and surface modification techniques, offering insights into the design of membranes with high performance for oil–water separation. Understanding relationship between grafting density, surface patterning, and membrane performance is crucial for advancing hybrid materials that address industrial challenges such as wastewater treatment and oil spill remediation. The insights gained from this study can be further refined by exploring different functional groups and surface modifications, broadening the applications of these membranes in industrial separation processes.