In order to control H2O/O2 selective permeability of starch based nanocompsites for food packaging, the addition of SiO2 nanoparticles was proven to be an effective method. The results suggested that the SiO2/hydroxypropyl starch (HPS) ratio was a feasible approach to regulate the film multi-scale structure. The H2O/O2 selective permeability was influenced by comprehensive factors including film short-range molecular conformation, crystalline structure and aggregated structure. The increase of micro-ordered region size was likely to favor the improvement of water vapor barrier property and the rise of compactness in this region seems to contribute to the oxygen prevention. Notably, the effect of film multi-scale structure on H2O/O2 selective permeability could be a supplement to conventional "tortuous path" theory for the explanation of barrier property improvement. This study could significantly guide to the rational design of H2O/O2 selective biodegradable food packaging in order to meet the requirement for different food systems.
Keywords: Multi-scale structure; Oxygen; Selective permeability; Starch-based nanocomposites; Water vapor.
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