Insights into the Hydration Layer of Reduced Graphene Oxides: A Computational Study.

Reduced graphene oxide (rGO) has emerged as a versatile material with diverse applications, particularly in aqueous environments. Understanding its interactions with water molecules is crucial for various fields, ranging from energy storage to sensing. In this study, we investigate the behavior of graphene and rGO in water, focusing on elucidating their wetting properties and the influence of oxygen-containing functional groups. Through extensive molecular dynamics simulations, we analyze the orientation and electrostatic dipole of water molecules near the rGO interface, revealing a direct correlation between rGO hydrophilicity and oxidation level. Specifically, we observe stronger hydrogen bonding networks near higher coverage rGO monolayers, indicating enhanced hydrophilicity. Furthermore, by studying water confined between rGO layers, we find uniform water transport with lateral self-diffusion coefficients comparable to bulk water, highlighting the potential of rGO membranes in various applications. Our findings provide insights into the atomic-scale interactions governing rGO-water interfaces, paving the way for the rational design of graphene-based materials for application in aqueous environments.