Study of antibacterial functional moisture barrier film based on Zn–Si composite oxide deposited by Plasma-Enhanced Atomic Layer Deposition system

This study investigated the development of Si-based antibacterial functional moisture barrier films using Zn-Si composite oxide thin films doped with Zn. Zn-Si composite oxide thin film was deposited on a flexible polyethylene terephthalate (PET) substrate using plasma-enhanced atomic layer deposition with diisopropylamino silane (DIPAS) and diethylzinc (DEZ). To investigate the structure and performance of the Si-based antibacterial functional moisture barrier film coated on PET, X-ray photoelectron spectroscopy, transmission electron microscopy, UV vis spectroscopy, water vapour transmission rate (WVTR), and antibacterial efficacy were evaluated. The optimised Zn–Si composite oxide exhibited optical transmittance of 90.78 % and a WVTR of 3.59 × 10 –4 g/m 2 .day. The long-term stability assessment revealed the impact of water solubility on the WVTR values after 72 h of DI water immersion, resulting in a 49 % increase to 5.35 × 10 –4 g/m 2 .day. The WVTR varied with the Zn content, with a 610 % increase in ZnO and 82 % increase in the SiO 2 thin films. The evaluation of the antibacterial properties against Escherichia coli and S. aureus indicated that the Zn–Si composite oxide films achieved sterilisation effects exceeding 99.99 %. The Zn–Si composite oxide thin film has potential applications in medical electronic displays that require antibacterial functionality along with future applications in functional optical films.