ON THE EXISTENCE OF A MAXIMUM SPEED OF WETTING

The motion of the three-phase contact line upon entrainment or drainage of glycerol and glycerol-water films on hydrophobic substrates is studied. It is established that the relative speed of the perimeter of wetting with respect to the solid surface remains constant under these conditions, regardless of the changes in film thickness and length due to variations in withdrawal velocity and time, respectively. This speed is equal to the largest speed of the contact line under steady-state kinetics of wetting and depends only on the material characteristics of the system. The results obtained present a new and direct experimental confirmation of the existence of a maximum speed of wetting as postulated by T. D. Blake and K. J. Ruschak.