Differential Ice Inhibition Mechanisms of Hydroxyl and Epoxy Groups on Graphene Oxide: A Molecular Dynamics Study

Cryopreservation has been widely applied in biomedicine, while intracellular ice formation (IIF) remains a critical obstacle limiting its effectiveness. As a tunable two-dimensional nanomaterial, graphene oxide (GO) exhibits remarkable ice-suppressing potential owing to its abundant surface functional groups. Based on molecular dynamics simulations, this study for the first time systematically disentangles the independent inhibitory mechanisms of hydroxyl and epoxy groups during ice formation, establishing a dual-mode pathway of “functional group regulation + interfacial structural stabilization”. We show that functional group type significantly affects the hydrogen-bond network at the GO–water interface. Epoxy groups, due to their low hydrophilicity, undergo notable lateral migration at the ice/water interface (up to 0.977 nm), maintaining ice front integrity and forming a dynamic mobile barrier that disrupts local ice growth, although potentially inducing off-target crystallization. In contrast, hydroxyl groups form strong hydrogen bonds and locally embed into the ice front with transient vertical fluctuations (0.172–0.290 nm), disrupting lattice order and inducing targeted defects. Furthermore, the spatial distribution of functional groups critically governs GO morphology and interfacial adhesion. Single functionalization induces asymmetric stress, spontaneous bending, and detachment from the ice surface, weakening its inhibitory effect. Dual functionalization, however, exhibits a synergistic enhancement, generating a stable ∼2.3 nm interfacial inhibition zone between ice and liquid water, while avoiding interfacial delamination. These findings deepen the mechanistic understanding of GO-mediated ice regulation and provide theoretical guidance for designing advanced cryoprotectants and anti-icing materials.