Plastic packaging effectively protects foods from mechanical, microbial, and chemical damage, but oxygen can still permeate these plastics, degrading foods. Improving the gas barrier usually requires metallic or halogenated polymeric coatings; however, both cause environmental concerns and metallic coatings block visible light and electromagnetic signals. This paper reports a design of a highly flexible, visible light and radio frequency transparent coating on commercial poly(ethylene terephthalate) (PET) film. Nanoscale blending was achieved between negatively charged cellulose nanofibers and positively charged chitin nanowhiskers by employing spray-assisted layer-by-layer assembly. Synergetic interplay between these highly crystalline nanomaterials results in a flexible film with superior barrier characteristics. The oxygen transmission rate was below 0.5 mL m-2 day-1. Moreover, this coating maintains its performance even when exposed to common hazards such as bending stress and hydration. The coating also notably reduces the haziness of PET with a negligible loss of transparency and provides effective inhibition of antibacterial growth. This "crab-on-a-tree" nanocoating holds high potential for biorenewable and optical and radio frequency transparent packaging applications.
Bibliographical noteFunding Information:
D.X.O. acknowledges funding from Korea Research Institute of Chemical Technology through Core Program (SI1809, KK1806) and the Technical Cooperation Project of Ulsan Metropolitan City-KRICT (SKO18US02). B.-S.K. acknowledges the financial support by the National Research Foundation of Korea (NRF-2017R1A2B3012148 and NRF-2018R1A5A1025208) and by the Ministry of Trade, Industry, and Energy (MOTIE), Institute for Advancement of Technology (KIAT) through the Encouragement Program for The Industries of Economic Cooperation Region (R&D, R0004883).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)