Molecular dynamics study on effect of structure on nucleation of water droplets

Non-equilibrium molecular dynamics simulations were conducted to investigate influences of structures at nanometer scales on nucleation of water droplets during condensation. As our calculation system, we employed a fluid system confined between two parallel solid walls where the nanostructures were attached to the bottom solid wall. The SPC/E model was used for water molecules, and the Lennard-Jones(LJ) potential was employed between solid atoms. The interaction between the fluid molecules and solid atoms was also described by the LJ potential function, and we simulated a hydrophobic condition by changing the interaction strength. Our simulation results show that, small clusters which consisted of the fluid molecules, tended to be formed near the side wall of the nanostructures. In addition, it was revealed that the nucleation rate was influenced by the presence of nanostructures, and the growth of nucleus wasn't in a consecutive manner. We also found that the size of the maximum cluster increases during a certain period of time before the cluster coalesces with another one. In the presence of the slit structures on the solid surface, the interfacial thermal resistance during condensation decreased in comparison with that without the nanostructures under the present calculation conditions.