An investigation on vapor condensation on nanopillar array surfaces by molecular dynamics simulation

Molecular dynamics simulation is used to investigate condensation of Argon vapor on nanopillar array surfaces made of copper. It is shown that condensation in the pillar array is nonuniform with respect to height. Effects of pillar height, pitch distance of nanopillars, wall subcooling and wettability on condensation of Argon vapor are discussed. It is found that higher pillars, denser pillars and stronger wall surface wettability can suppress vapor condensation at the bottom of a nanopillar array, making vapor more likely to condense in the upper section of the array. It is also shown that the condensation peak in the nanopillar array can be shift from bottom to top with the increasing wall subcooling. The formation of Cassie state droplets is observed and discussed.