Properties enhancement of antimicrobial chitosan-deposited polylactic acid films via cold plasma treatment

The present study aimed to understand the effect of dielectric barrier discharge cold plasma (DBD-CP) technology on the antimicrobial chitosan deposition and the properties enhancement of polylactic acid (PLA) films. The results indicated that DBD-CP was an effective method for improving the adhesion and surface hydrophilicity of PLA, facilitating the deposition of chitosan coating. This modification was attributed to the increased surface roughness, as well as the presence of polar functional groups observed through atomic force microscopy, surface free energy and Fourier transform infrared spectroscopy analysis. The study further revealed that both water resistance and mechanical properties were significantly improved after DBD-CP treatment, which was positively correlated with the amount of chitosan deposited on the PLA surfaces. Following comprehensive evaluation, the treatment at 75 W was determined as the optimal condition for enhancing the properties. Additionally, the modified film exhibited strong antimicrobial activity against Staphylococcus aureus. Consequently, the DBD-CP technology could be a promising tool for better utilization of PLA-based materials in the antibacterial food packaging industry.