Fabrication and Characterization of Carrageenan/ZnO/Chitosan Composite Films

In this study, a high-performance carrageenan/ZnO/chitosan composite film (F_CA/ZnO/CS) was fabricated by the solution/dispersion casting method and layer-by-layer method. The first layer was nano-ZnO dispersed in carrageenan solution, and the second layer was chitosan dissolved in acetic acid. The morphology, chemical structure, surface wettability, barrier properties, mechanical properties, optical properties, and antibacterial activity of F_CA/ZnO/CS were evaluated compared with a carrageenan film (F_CA) and carrageenan/ZnO composite film (F_CA/ZnO). This study revealed that the Zn element in F_CA/ZnO/CS existed in the form of Zn²⁺ in F_CA/ZnO/CS. There existed electrostatic interaction and hydrogen bonding between CA and CS. As a result, the mechanical strength and transparency of F_CA/ZnO/CS were enhanced and the water vapor transmittance of F_CA/ZnO/CS was decreased compared with that of F_CA/ZnO. Furthermore, the addition of ZnO and CS greatly enhanced the antibacterial activity of Escherichia coli and also had a certain inhibitory effect on Staphylococcus aureus. F_CA/ZnO/CS is expected to be a potential candidate material for food packaging, wound dressings, and various surface antimicrobial coatings.