CRITICAL RADIUS OF HOLES IN LIQUID COATING

In this paper, we focus our interest on the stability of a thin liquid film deposited on a non-wetting surface. The film is metastable and d ewets by nucleation and growth of dry patches. Dry patches grow only i f the radius is greater than a critical value, R(c). We measured R(c) in the case of polythene terephtalate coated by glycerol or di-iodomet hane as a function of e, the thickness of the film. The experimental r esults agree well with the predicted formula [5, 6] R(c) = e/l sin the ta(e), where theta(e) is the equilibrium contact angle and l a logarit hmic function of R(c).