Design strategies for sustainable gas barrier coatings in food packaging via wet deposition technologies

The gas barrier properties of packaging materials play a pivotal role in determining the fate of packaged food products. While multilayer composites provide precise control over gas transport, the growing demand for sustainability is stimulating research into barrier layers compatible with key polymer end-of-life pathways, including recyclability or composting. This review examines the technological advancements and design strategies for barrier coatings in food packaging, with a focus on wet coating technologies for polymers. The first section introduces the permeation theory and mass transport phenomena in multilayers. The second part delves into assessing various barrier coating systems, comparing key wet coating technologies reported in scientific literature, including organic-inorganic hybrid, nanocomposite, and multilayer coatings. The final section discusses significant findings and offers insights into the design of high-barrier wet coatings while considering their end-of-life implications and potential for industrial upscaling. This comprehensive review aims to highlight the critical role of innovative high-barrier coatings’ in overcoming the limitations of current multilayer composites, thereby fostering improved sustainability and preservation performance in food packaging applications.