Surface modification of biodegradable polymers by low temperature plasma for improving their performances as food packaging

Biodegradable polymers are viewed asa promisingeco-friendly solutionto replace conventional plastic polymers as packaging materials, reducing the enormous environmental impact that the latter involve[1]. However, biodegradable plastics still occupy a rather restrictedsection of the plastic food packagingmarketduesome limitations includingtheirpoorgas barrier andUV protectionproperties[2].In fact, both oxygen and UV light lead to oxidation processeswhich alter food quality and produce toxic compounds [3,4].In this regard, low temperature plasma technique can be exploited to fabricate multifunctional polymeric surfaces with significant enhanced performances. This approach is completelyenvironmentally friendly avoiding the use of toxic solvents or high temperatures that coulddamage the polymer structure[5,6]and it is crucial to extendthe use of biodegradable packaging and preservethe food quality.In this work we report onsurfacesmodificationsof two commercial biodegradable polymers by low temperature plasma processes. In particular, tungsten oxide (WOx) thin films were deposited by plasma magnetron sputtering on poly(lactic acid) (PLA)in orderto enhanceitsperformances in terms of barrier to oxygen and UV light protection. Moreover, plasma etching was employedto tailor the surface morphology of poly(butylene succinate) (PBS)resulting in a packaging with antimicrobial effect due to the nature inspired contact-killing mechanism.