THE INFLUENCE OF TITANIUM DIOXIDE IN THE PVK MATRIX ON ANTI-BACTERIAL PROPERTIES, ELECTRICAL RESISTANCE AND RESISTANCE TO UV RADIATION

In the present study the poly (N-vinylcarbazole) (PVK) is doped with nano-crystalline titanium dioxide (TiO2). The solutions of the PVK-TiO2 and neat PVK in the DMSO were prepared, followed by a gradual evaporation of the solvent until the mixture became viscous. The viscous solution was drop-cast onto a pre-cleaned glass substrate (ITO). A polymer thin film was formed after slow solvent evaporation under ambient conditions for 12h. Thin films of PVK-TiO2 composites show a porous microstructure (SEM). The complexation and the ultraviolet resistance of the composite were confirmed by Fourier transform infrared spectroscopy (FTIR) and UV-Visible studies. The antibacterial activity was tested with various concentrations, 10(-2)M, 3.10(-2)M and 5.10(-2)M of doping, with Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus. The electrical resistance of the samples of PVK and these complexes is based on the Automatic Mapping Four Point Probe System. Moreover, the TiO2 based Poly (N-vinylcarbazole) (PVK) exhibited a remarkable variation at higher concentrations as compared to that of the pure poly (N-vinylcarbazole) film. The antimicrobial activity against gram negative and gram positive bacteria increased with the increase in the concentrations of TiO2 and the maximum inhibition of bacteria growth was observed in PVK-TiO2(5.10(-2)M) composites with Escherichia coli. This is due to the higher concentrations of TiO2, activated surface area and better dispersion of TiO2 on PVK. The results of SEM confirm the presence of TiO2 in the composite, which consequently modifies the morphology of the film significantly.