A study of a nano-sized water droplet’s transition from a flat surface to a pillared surface

The ability to control the hydrophobicity of a surface is of importance to many industries. The dynamic behavior of nano-sized water droplets moving from a flat surface to a pillared surface using molecular dynamics simulations was investigated. Simulations were carried out in two steps. In the first computational step, the initial group of water molecules reached equilibrium on a flat graphite surface. In the second computational step, a constant force was applied to the water droplet and the motion of the water droplet was evaluated as it moved from the flat surface to the pillar-type surface. The movement of the water droplet could be grouped into three different categories and depended on the pillar height and the magnitude of the applied force. The results showed the strongest body force with a pillar height of 6 graphite layers allowed most of the water molecules to move along the top of the pillars. In conclusion, a strong force and pillar height approximately half of the droplet height displayed the best transition from a flat surface to a pillared surface.