Plasma pre-treatment and TiO2 coating of PMMA for the improvement of antibacterial properties

The antibacterial properties of polymethyl methacrylate (PMMA) are enhanced by coating with TiO2 films. The transparent TiO2 films on plasma-treated PMMA are prepared by sol-gel dip coating. The modified surfaces are characterized by XRD, AFM, ATR-FTIR, SEM, UV-vis spectroscopy, and contact angle measurements. Finally, the antibacterial properties are evaluated using the method of plate-counting of Staphylococcus aureus (gram positive) and Escherichia coli (gram negative). It is found that the anatase-TiO2 film is well-conglutinated on PMMA surface with an average crystallite size of ca. 4 nm. The as-prepared TiO2/PMMA exhibits excellent photoinduced antibacterial effect for the sterilization of bacteria under indoor natural light, and about 100% of both bacteria are inactivated within 2 h illumation. Compared to PMMA without any treatment, the superior anti-adhesion capability of the TiO2/PMMA surface is also demonstrated.