Dewetting of solids by the formation of holes in macroscopic liquid films

Abstract

A macroscopic liquid film supported on a solid surface rupture due to hole formation when its thickness is reduced to a certain critical thickness. A theory is presented for obtaining the dependence of the critical thickness on the solid and liquid interfacial tensions and the equilibrium angle of contact between solid and liquid. The theory is based on the thermodynamic argument that when the free energy of the film-solid system becomes equal to or greater than the free energy after the formation of a hole in the liquid film, the film breakup becomes possible. The critical thickness increases with the contact angle in a nonlinear fashion and is directly proportional to the hole radius. The predicted variation of the critical thickness with the contact angle is in qualitative and quantitative agreement with the available data on the rupture of thin, macroscopic (several hundred micrometers thick) liquid films. The present theory provides a criterion for the design of surfaces that remain wettable by liquid films of given thicknesses.