Molecular Dynamics Study of Liquid Condensation on Nano-structured Sinusoidal Hybrid Wetting Surfaces

Abstract: Although real surfaces exhibit intricate topologies at the nanoscale, rough surface consideration is often overlooked in nanoscale heat transfer studies. Superimposed sinusoidal functions effectively model the complexity of these surfaces. This study investigates the impact of sinusoidal roughness on liquid argon condensation over a functional gradient wetting (FGW) surface with 84% hydrophilic content using molecular dynamics simulations. Argon atoms are confined between two platinum substrates: a flat lower substrate heated to 130K and a rough upper substrate at 90K. Key metrics of the nanoscale condensation process, such as nucleation, surface heat flux, and total energy per atom, are analyzed. Rough surfaces significantly enhance nucleation, nearly doubling cluster counts compared to smooth surfaces and achieving a more extended atomic density profile with a peak of approximately and improved heat flux. Stronger atom-surface interactions also lead to more efficient energy dissipation. These findings underscore the importance of surface roughness in optimizing condensation and heat transfer, offering a more accurate representation of surface textures and a basis for designing surfaces that achieve superior heat transfer performance.