Effect of wall material on water nanovortices formation in 2D long open type nanocavity. Molecular Dynamics study

Abstract

In our earlier papers [18,19] we showed the dependence of water nanovortex structures in long open type quartz nanocavities on their sizes. Here we study the effect of wall material limiting the water flow on the nanovortex structure.The artificial wall material was constructed by omitting electric charges in ClayFF [8] molecular model of quartz. It caused weaker interactions between molecules of the wall and water during the NEMD simulation of the flow, as compared to the case when the water flow was limited by the quartz [8] wall.Hydrodynamic bulk parameters obtained by averaging the NEMD simulation data of 19ns water flow in two nanochannels of 22nm height with perpendicular nanocavities of 25.2nm length and 7nm width of different wall material were compared and analysed.The findings show that the wall material has a significant influence on the water flow structure and main nanovortex position. In the nanocavity whose wall material interacts stronger with water molecules the main vortex centre shifts to the front wall of the nanocavity and is situated closer to main nanochannel axis than in nanocavity where forces of intermolecular interactions between the wall material and water molecules are weaker. Our findings and conclusions obtained from this paper show nanovortices as potential promising tools for applications in nanobiological and nanofluidic devices.