Organic/Inorganic Hybrid Sol-Gel Derived Hard Coatings on Plastics

Abstract

ABSTRACTWe investigated sol-gel derived silica based hard coatings on modified polyester substrates. The silica network was modified by incorporating an organic component and adding transition metal oxides. These modifications resulted in tailored thermal, optical and mechanical properties of the coatings. Various low temperature densification techniques were studied including appropriate sol-preparation procedure, enhanced solvent evaporation, ultraviolet (UV) irradiation, and low-temperature (below 150°C) heating. Oxygen plasma etching was applied to improve the adhesion of the sol-gel coatings on the plastic surface. Nanoindentation analysis revealed that the sol-gel coatings have a surface hardness up to 2.5±0.27 GPa, approximately an order of magnitude higher than that of the plastic surface.