École Nationale Supérieure de
Techniques Avancées

Abstract

This work has been performed at the Laboratoire de physique des solides (Orsay, France) under the Responsability of Frederic Restagno and Liliane Léger in collaboration with the ophtalmic glass manu-facturer Essilor. The engineers in charge of the project in Essilor are Frederic Mouhot and Jean-Pierre Degand working in the Test & Developments group of the R&D Center of Saint-Maur des Fosses (France). An organic ophthalmic glass is usually recovered by several coatings. The application of coatings to the front and rear faces makes the ophthalmic lens even more effective. It allows protection against scratches and protection against reflections and smudgesĚ The aim of this work was to improve the physical understanding of the physical mechanisms of smudge adhesion on surfaces and to characterize the anti-adhesive properties of several top coats. In order to characterize weakly adhesive surfaces, a test in which capillary forces are opposed to adhesive strength, instead of elastic forces as in usual JKR tests has been developed by two previous post-doctoral studies, [1] and [2]. The surface under investigation is put into contact with a liquid bath and then pulled-off. The formation and breakage of a capillary bridge between liquid bath and the spherical surface (large radius of curvature, R=100 mm) is recorded. Using water, it has been showed that the capillary bridge technique is really efficient to discriminate the coatings and is a very sensitive technique to measure the contact angles on curved surfaces averaged over the whole glass lens surfaces. In a second part, using the technique with silicon oils, the entrainment of a liquid film on the surfaces very sensitive to the surface coating has been studied. In particular we have showed that the dynamics of the liquid film is very similar of previous studies on dewetting.