Flexible high-barrier (HB) materials offer exciting potential applications with relevance to numerous key industries including packaging. Despite their promising potential applications, the existing flexible HB materials have limited applications due to prevailing drawbacks such as poor optical clarity and limited scalability. The objective of this study was to investigate a new scalable approach for flexible HB fabrications with good optical properties. This new approach relies on the use of hydrophobic fabrication of polymers that reduces the solubility of the permeants (oxygen, water vapors) in a film/plastic and hence the barrier properties can be improved drastically. In this study, polyvinyl alcohol (PVOH) was selected as a model polymer to increase its water vapor barrier properties and oxygen barrier properties at high relative humidity. PVOH is a biodegradable synthetic polymer with good optical clarity and excellent oxygen barrier under dry conditions. However, at high relative humidity, the barrier properties are drastically reduced due to the bonding of hydrogen between water and PVOH. When a thin layer of polydimethylsiloxane polyurethane (PDMS PU) was applied onto PVOH films, the water vapor and oxygen barrier properties of PVOH were drastically improved as quantified by permeability and other analytical tests. Interestingly, the tensile strain and impact strength of the coated films were enhanced after applying the coating. Besides, the obtained coated films were optically clear that makes them appealing for packaging applications. This novel HB fabrication approach can be applied to other packaging plastic such as PET, PLA, LDPE, etc. -- Abstract.
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