Nature-inspired antibacterial poly (butylene succinate) (PBS) by plasma etching nanotexturing for food packaging applications

Abstract

Antibacterial surfaces are crucial to hinder the spread of pathogens infections, especially when high-touch surfaces (HTS) are involved, as in the case of food packaging. Nature can be inspiring, offering plenty of nanotextured surfaces with high antibacterial activity. Herein, poly(butylene succinate) (PBS), one of the most reliable biodegradable plastic used in food packaging, was nanotextured by a low pressure plasma oxygen etching. Moreover, the deposition of SiOX coatings ≈15 nm thick by plasma enhanced chemical vapor deposition (PECVD) was carried out to improve gas barrier properties of the nanotextured polymers. Based on experimental findings, a hypothesis for the nanotexturing mechanism in our plasma experimental set-up has been figured out. The antibacterial properties were tested against E. coli and S. aureus, showing in both cases a strong inhibitory effect by a factor of >4 log10 CFU cm−2. Finally, the oxygen diffusion permeability coefficients (PO2) were also measured, and the oxygen transmission rates (OTR) were calculated as an indicator of the gas barrier performance of the samples. As expected, plasma etching impacted negatively on the oxygen permeability. However, by coating with SiOx, the treated PBS showed a 30 % decrease of the OTR compared even to the untreated PBS.