Barrier Properties of Ordered Multilayer Polymer Nanocomposites
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During the last decade, the development of a novel type of composite material led to a significant improvement of mechanical, thermal, and vapor transport properties of films and coatings. Such materials are based on finely dispersed or interspersed organic–inorganic components down to their nanodimensions and are characterized by an intimate contact of their components and their nanodimensionality, whereas their specific architecture (crystal structure, morphology, etc.) is often preserved in the material. This results in a particularly strong interaction between components and an optimal summation of their properties. Especially interesting are nanocomposites in which one or more components have been oriented because orientation often results in additional strengthening and enhancement of properties. Coatings and films from such materials are endowed with exceptional mechanical and thermal stability, allowing for small thicknesses and making them very interesting for various applications. In this article, we describe the resistance to the vapor penetration of multilayer nanocomposites with a focus on the resistance to gas/vapor diffusion, rather than on their separation ability (permselectivity). Such properties acquire a special importance in the packaging of materials such as food, beverages, chemical and medical packaging, etc.