Molecular dynamics simulation on wetting behaviors of n-octane and water droplets on polytetrafluoroethylene surfaces

Abstract Wetting behaviors of n-octane, water and their mixture nanodroplets on smooth and rough polytetrafluoroethylene substrates were investigated by molecular dynamics simulation. Results showed that wetting behaviors of two pure droplets differed significantly on the smooth surface with equilibrium contact angles being about 20° for n-octane and 92° for water. On the fence-type rough surface, the n-octane droplet presented in the Wenzel state and the water droplet was in the Cassie state at 0.33 of phase area fraction and 3.67 of roughness factor. The rough surface specially constructed in this work could realize a preliminary separation of the n-octane–water mixture.