Heavy-ion ERDA and spectroscopic ellipsometry characterization of a SiOC:H layered structure as functional coating on polymeric lenses

Abstract

In order to improve the optical and mechanical performance of plastic ophthalmic lenses the use of surface coatings is necessary. However, the application of such coatings can be limited by bad adhesion to the substrate. One way to overcome this drawback is the use of a layered structure consisting of an adherent layer, an abrasion resistant hard layer and an antireflective (AR) multilayer (ML) stack. In this work we study the preparation of SiO x C y :H layered coatings to increase the mechanical durability of polymeric substrates and to accommodate gradually an external dielectric SiO 2/TiO 2 AR-ML. The coatings were grown by plasma assisted chemical vapor deposition (PACVD) using a mixture of hexamethyldisiloxane (HMDSO) and O 2. The possibility of producing the whole layered stack by adjusting the HMDSO:O 2 ratio was demonstrated. The composition and elemental profiles of the different layers were measured by ERDA using 35 MeV Cl-ions. A polymeric-like gradient layer could be formed followed by a buffer layer Si 28O 47C 15H 10 with a nearly constant composition. The variation of the elemental composition does not affect significantly the optical properties, which are close to that of SiO 2.