Therefore, we suggest that future NEMD simulations use the weak (ClayFF Surface hydroxylation and the inclusion of interfacial water nanofilms also significantly impact the ITR. For water films thicker than one monolayer, the ITR converges to a consistent value (R k ≈ 10 m 2 K GW -1 ) that is independent of the solid-liquid interaction strength. This value is primarily governed by the ITR at the water/PAO interface, with strong hydrogen bonding between the water film and the hydroxylated surface resulting in a very small hematite/water ITR. Previous NEMD simulations reported a similar ITR at the water/octane (R k = 15 m 2 K GW -1 ) and water/benzene (R k = 6 m 2 K GW -1 ) interfaces, with the latter having stronger intermolecular interactions and increased first layer density. Thus, our value of the ITR sits between those previously measured for water/hydrocarbon interfaces. By incorporating surface hydration, closely reflecting the nanoscale surface structure expected in experiments under ambient conditions, these simulations offer a more precise estimate of the ITR at the hematite/PAO interface. This ITR value should prove useful for thermal modelling of systems such as immersion cooling systems for electric vehicle batteries, 8 oil-based iron oxide nanofluids, and beyond. We also hope that the ITR value from our simulations will be experimentally validated for the hematite/PAO interface using thermoreflectance-based techniques 7 in the near future.