Interfacial thermal resistance between nano-confined water and functionalized silica: Molecular dynamics simulations

Abstract

Nanoscale engineering enables precise tuning of materials properties through surface functionalization, impacting energy conversion and heat dissipation in nanodevices. We used molecular dynamics simulations to observe the impact of grafting hydrophobic trimethylsilane molecules on the interfacial thermal resistance between silica and water at the nanoscale. As the level of hydrophobicity increases, both the cosine of the contact angle and the water density peak near the interface exhibit linear trend. The hydrogen bond network of water, initially completed by the silanol (Si-OH) groups of the silica surface, is disrupted by the hydrophobic molecules. This results in an exponential variation of the interfacial thermal resistance. We finally provide a law that relates the cosine of the contact angle and the interfacial thermal resistance between functionalized silica and water. Our results are of great interest for experimental researchers using Scanning Thermal Microscopy under humid environments and the multiscale heat transfer modeling in functionalized nanoporous materials.