Effect of nanostructures on evaporation and explosive boiling of thin liquid films: a molecular dynamics study

Abstract

Molecular dynamics simulations have been employed to investigate the boiling phenomena of thin liquid films adsorbed on a nanostructured solid surface. The molecular system was comprised of the following: solid platinum wall, liquid argon, and argon vapor. A few layers of the liquid argon were placed on the nanoposts decorated solid surface. The nanoposts height was varied keeping the liquid film thickness constant to capture three scenarios: (i) liquid-film thickness is higher than the height of the nanoposts, (ii) liquid-film and nanoposts are of same height, and (iii) liquid-film thickness is less than the height of the nanoposts. The rest of the simulation box was filled with argon vapor. The simulation was started from its initial configuration, and once the equilibrium of the three phase system was established, the wall was suddenly heated to a higher temperature which resembles an ultrafast laser heating. Two different jump temperatures were selected: a few degrees above the boiling point to initiate normal evaporation and far above the critical point to initiate explosive boiling. Simulation results indicate nanostructures play a significant role in both cases: Argon responds very quickly for the nanostructured surface, the transition from liquid to vapor becomes more gradual, and the evaporation rate increases with the nanoposts height.