Properties of TiO2/PDMS-Ag Composites as Antibacterial Self Cleaning

Abstract TiO 2 and TiO 2 -PDMS/Ag (PDMS = polydimethylsiloxane) composites have been prepared. The synthesis was carried out by preparing TiO 2 using ball milling technique for 6, 8 and 10 hours, with the composition of TiO 2 : ball milling = 1:15; 1:20; and 1:25 (g/g). Furthermore, the TiO2-PDMS/Ag composite was synthesized through the solvent dispersion method with the aid of ultrasonication. The preparation of TiO 2 -PDMS/Ag composites was carried out with several compositions of TiO 2 , PDMS and Ag, as well as milling times, aiming to determine the effect of compositions and time of ball milling process on decreasing of TiO 2 particle size. The addition of Ag to the TiO 2 -PDMS composites was carried out to investigate the effect of Ag on the antibacterial activity. TiO 2 -PDMS/Ag composite coating on glass was done by spray coating method. While the antibacterial activity was measured by determining the zone of inhibition by disc diffusion method against Staphylococcus aurous and Escherichia coli. The results exhibited that the ball milling treatment and milling time affected the change in the crystal size of TiO 2 . The highest composition of TiO 2 : ball milling at 1:25 for 10 hours was able to reduce the crystal size of TiO 2 from 65.81 nm to 46.17 nm. The other hand, the observation of the physical properties of the contact angle of glass coated TiO 2 -PDMS/Ag composites before irradiation obtained 107° and after irradiation with visible light the contact angle decreased to 56°, which shows that the TiO 2 -PDMS/Ag composites exhibit photocatalytic activity in the presence of TiO 2 /Ag. Furthermore, the observation of antibacterial activity on the TiO 2 -PDMS/Ag as a self-cleaning photocatalytic materials resulted that the largest inhibition zone reached 11.37 mm, so that the TiO 2 /PDMS-Ag composites had great potential as an active antibacterial self-cleaning.