In this study, super-hydrophobic coatings suitable for the functionalization of conventional packaging paper and bioplastic films were developed. To do so, three different kinds of compostable/biodegradable biopolymers, i.e. polylactide, poly(ε-caprolactone), and biowaste derived poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) were used, processed by electrohydrodynamic processing (EDHP). As a first step, the ultrathin biopolymer fibers were deposited onto the substrates by electrospinning and, thereafter, functionalized silica nanoparticles were sequentially electrosprayed. The materials were finally optimized by low temperature annealing to further promote substrate adhesion. The films were characterised in terms of morphology, contact angle, thermal, barrier and interlayer adhesion in order to shed some light into the relationship between structure, processing and properties. The resultant materials presented a hierarchical micro/nanostructured surface with an apparent contact angle (WCA) higher than 155° and sliding angle (SA) lower than 10°. It was observed that PHA nanostructured coatings showed the best performance in terms of the overall water vapor permeance in the case of the paper substrate, and, interestingly, the super-repellent properties remained high when some foodstuffs where used instead of water. These biocoatings can have significant interest in packaging applications, where fully compostable/biodegradable packaging structures, compatible with circular bioeconomy strategies, are put forward to, among other necessary functions, help the necessary reduction in food waste.

Super-Hydrophobic biocoatings of interest in food packing applications

ACS Spring Meeting 2021

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