Functional barrier coatings on the basis of hybrid polymers
With barrier coating materials, namely, hybrid polymers (ORMOCERÂ®), it is possible to obtain excellent barrier properties against oxygen, water vapor, and flavor permeation. These hybrid polymers can be synthesized by the sol-gel technique. If extremely low permeation values are needed, the combination of hybrid polymer coatings with thin inorganic oxidic layers (e.g., SiOx, AlOx) is very effective. These passive barrier layers can be further improved by the combination with active barrier layers, e.g., oxygen scavenger layers. The development of novel biodegradable polymer coatings (bioORMOCERÂ®) was achieved by replacing the nonbiodegradable organic components with biodegradable components. The materials can be equipped with additional functions (e.g., antimicrobial, UV-protection properties) and can even be used successfully on the most difficult surfaces to be coated (fluoropolymer-based materials and polyolefins) as adhesion promoters and surface planarization lay ers. This approach makes these functional coating materials promising candidates for special applications in the food packaging industry as well as for sophisticated applications in technical areas: the encapsulation of sensitive organic devices like solar cells, organic light-emitting diodes, or polymer electronic systems. Promising formulations and methods for quality assurance in production processes have already been developed.