A Scratch-Resistant Single-Layer Antireflective Coating by a Low Temperature Sol-Gel Route

A novel quarterwave-thick narrow-bandwidth antireflective coating has been developed for both plastic and vitreous substrates by a sol-gel route. This coating has revealed pronounced scratch-and climatic-resistance under adverse conditions. The single-layer coating consists basically of a composite material made of silica as the discontinuous phase and of a polytetrafluoroethylene-derived (Teflon 1) organic polymer as the continuous phase. This leads to fluorine-containing colloidal silica product, or a so-called Flucosil coating. The coating is applied by spinning or dipping from specific solutions at room temperature followed by a mild and short heat treatment. In addition to remarkable abrasion and environmental resistance properties, such coatings have displayed excellent laser-induced damage threshold levels, surpassing uncoated substrates. We hope such a product might open new perspectives concerning household articles, architectural optical thin-films, ophthalmic uses, and so on.