Solution-deposited amorphous titanium dioxide on silicone rubber: A conformal, crack-free antibacterial coating

Controlled formation of thin oxide films on polymers provides an increasingly important too] for modifying the polymer interface without changing its bulk properties. The successful application of a titania thin film by liquid phase deposition (LPD) from water under near-ambient conditions onto polydimethylsiloxane (PDMS) substrates has been achieved. This offers a convenient, non-line-of- sight-limited method for imparting titania-like properties to the surface of the PDMS elastomer. Conditions have been found for priming the surface of the PDMS to provide for good adhesion of the oxide layer and a suitable combination of film deposition and film drying conditions are described that provide a conformal crack-free titania coating on the PDMS. This is the first report of LPD oxide formation on an elastomer. The application of such titania coatings to controlling bacterial adhesion and growth on the polymer surface is also described. The adhesion of both Gram-negative and Gram-positive bacteria to the modified surfaces is reduced. This reduction is further enhanced by UV irradiation of the TiO2 overlayer prior to introduction of the bacteria.