Lubrication approximation was used to analyze the evolution of ultra-thin liquid film in the dynamic wetting of complete wetting fluid at low capillary number. The results indicate that van der Waals forces have an important effect on the interfacial profile of the ultra-thin liquid film in the vicinity of the apparent contact line.For repulsive van der Waals forces

the disjoining pressure is larger than zero

and the vapor pressure outside the interface is higher than the pressure of the liquid film.The thickness profile of the ultra-thin liquid film increases with the increase of van der Waals forces.Furthermore

the capillary number also affects the thickness profile of the film in that higher capillary number leads to thicker liquid film.