Aluminum-doped zinc oxide coatings on polylactic acid films for antimicrobial food packaging

• Published in: Thin solid films Vol. 645; pp. 187 - 192
• Main Authors: Valerini, D., Tammaro, L., Di Benedetto, F., Vigliotta, G., Capodieci, L., Terzi, R., Rizzo, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2018
• Subjects: Antibacterial coating; Film extrusion; Food packaging; Nanostructured aluminum-doped zinc oxide; Polylactic acid (PLA); Sputtering; Food packaging; Antibacterial coating; Nanostructured aluminum-doped zinc oxide; Polylactic acid (PLA); Film extrusion; Sputtering
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2017.10.038

Polylactic acid (PLA) is safe for contact with food, flexible and highly transparent to visible light, so it is widely used for food packaging applications. The addition of proper surface coatings can provide further advantages, such as antimicrobial activity and optimized optical properties. To this aim, nanostructured aluminum-doped zinc oxide (AZO) coatings were sputter-deposited onto extruded PLA film to functionalize its surface, using different sputtering power. Morphological, structural and optical characterizations were performed on uncoated and coated films, demonstrating uniform coverage of the PLA substrate with polycrystalline AZO coatings and high visible transparency. Spectrophotometric measurements carried out on physiological saline solutions containing the samples revealed low release effects from the uniformly-coated films. Finally, the sputter-coated samples exhibited strong antibacterial activity against Escherichia coli. The results of this preliminary study indicate that AZO-coated PLA films are promising materials for environment-friendly active packaging applications. •Aluminum-doped zinc oxide (AZO) coatings are sputtered onto polylactic acid (PLA).•The AZO-coated PLA films are promising for active food packaging applications.•The coatings are nanocrystalline, with different zinc and aluminum oxide phases.•The coated films show UV blocking properties and high visible transparency.•Low release effects of particles and fast antibacterial activity are observed.