Zein films with ZnO and ZnO:Mg quantum dots as functional nanofillers: New nanocomposites for food package with UV-blocker and antimicrobial properties

• Published in: Polymer testing Vol. 91; p. 106709
• Main Authors: Schmitz, Francielle, Silva de Albuquerque, Maria Beatriz, Alberton, Michele Debiasi, Riegel-Vidotti, Izabel Cristina, Zimmermann, Lizandra Maria
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2020
• Subjects: Antibacterial materials; Bioplastic; Nanocomposites; Quantum dots; UV-blocker; ZnO; ZnO; UV-blocker; Nanocomposites; Quantum dots; Bioplastic; Antibacterial materials
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2020.106709

The preparation of a new nanocomposite by combining zein and quantum dots (QDs) was the main interest of the present work. By the sol-gel method, colloidal ethanolic dispersions of zinc oxide (ZnO) particles and ZnO particles doped with magnesium (II) (ZnO:Mg) were obtained, sized 4.26 and 3.65 nm, respectively, as determined by UV–Vis spectroscopy. The prepared QDs were used as nanofillers in order to obtain zein-based nanocomposite films, which displayed good visual appearance, homogeneity, and transparency. The presence of QDs increased the hydrophobicity and reduced, up to three times, the amount of water uptake of the composite films when compared to pure zein. Those effects were more pronounced for ZnO:Mg QDs. TEM, FTIR, and fluorescence microscopy analysis indicated that zein interacts more effectively with ZnO:Mg than with ZnO. In addition, and most importantly, the presence of QDs in the films showed an important advantage when compared to those of pure zein: the extended UV-blocking in the absorbance spectra. The antimicrobial assays demonstrated that the ZnO NPs, loaded into zein films, are promising antibacterial materials since the inhibition of growth of S. aureus reached (96.5 ± 4.9)% at 44.8 wt% of ZnO NPs. Therefore, the nanocomposites show promising features for the development of food packaging, UV protective films, and for the development of new and sustainable materials. [Display omitted] •Nanocomposites with zein and ZnO quantum dots as a substitute of synthetic plastics.•Zein@ZnO QDs and Zein@ZnO:Mg QDs in food packaging with UV-blocker properties.•Nanomaterial obtained with potential for food packaging with antimicrobial activity.•Nanocomposites obtained with higher hydrophobicity than pure zein.•Transparent bioplastic with zein and ZnO quantum dots.