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

Abstract

TiO2 and TiO2-PDMS/Ag (PDMS = polydimethylsiloxane) composites have been prepared. The synthesis was carried out by preparing TiO2 using ball milling technique for 6, 8 and 10 hours, with the composition of TiO2: 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 TiO2-PDMS/Ag composites was carried out with several compositions of TiO2, PDMS and Ag, as well as milling times, aiming to determine the effect of compositions and time of ball milling process on decreasing of TiO2 particle size. The addition of Ag to the TiO2-PDMS composites was carried out to investigate the effect of Ag on the antibacterial activity. TiO2-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 TiO2. The highest composition of TiO2: ball milling at 1:25 for 10 hours was able to reduce the crystal size of TiO2 from 65.81 nm to 46.17 nm. The other hand, the observation of the physical properties of the contact angle of glass coated TiO2-PDMS/Ag composites before irradiation obtained 107° and after irradiation with visible light the contact angle decreased to 56°, which shows that the TiO2-PDMS/Ag composites exhibit photocatalytic activity in the presence of TiO2/Ag. Furthermore, the observation of antibacterial activity on the TiO2-PDMS/Ag as a self-cleaning photocatalytic materials resulted that the largest inhibition zone reached 11.37 mm, so that the TiO2/PDMS-Ag composites had great potential as an active antibacterial self-cleaning.