Effect of Liquid-Solid Interaction on Liquid Transport Properties in a Nanometer Capillary Tube

In the present paper, molecular dynamics is applied to study the effect of interaction between liquid-solid on liquid transport properties, especially a stagnant layer to a slip layer, in a circular nano tube under a constant injection flow rate boundary condition. In simulations, a full 12-6 Lennard-Jones potential, truncated at 2.2σ, is used to govern the interaction between liquid-liquid and liquid-solid molecules. Six cases with different interactions (or energy scales) between liquid-solid are carried out. The non-equilibrium molecular dynamics (NEMD) simulation results show that the interaction between liquid-solid causes a wavelike density distribution in normal wall direction and the amplitude of wave is proportional to the interaction between liquid-solid; the interaction between liquid-solid dominates the motion of first liquid layer close to the solid substrate, i.e., the strong interaction between liquid-solid can result in the a stagnant layer; the weak interaction between liquid-solid produces a slip layer and the intermediate interaction between liquid-solid made a slip and sub-slip layers.