Molecular dynamics simulation study of the dynamics of fluids at solid‐liquid interfaces

Abstract The dynamics of fluids at solid‐liquid interfaces is investigated. In particular, we consider a simple Lennard‐Jones fluid as well as a melt of hexadecane chains. For the Lennard‐Jones fluid, the numerical results are compared with analytical calculations based on the diffusion equation, which shows that the numerical results can very well by described by the solution of the diffusion equation for reflecting surfaces. The diffusion coefficient is practically independent of the position within the film, although the fluid is inhomogeneous perpendicular to the surface. In contrast, the dynamics of the centers of mass of hexadecane molecules perpendicular to repulsive surfaces is severely slowed down due to their extended and anisotropic nature and cannot be described by a single particle diffusion equation.