We have used optical microscopy, atomic force microscopy, and ellipsometry to study the dewetting of films of a perfluoropolyether polymer on silicon substrates. The disjoining pressure of these films is determined, for the first time for a dewetting system, by using noncontact atomic force microscopy to measure the dimensions of the liquid dewetting droplets. The determined disjoining pressure explains the different dewetting processes observed for different initial film thicknesses and is dominated by structural forces and by the inability of the polymer to spread on its own monolayer.

• Received 2 November 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.3496