UV-Degradation Effect on Optical and Surface Properties of Polystyrene-TiO2 Nanocomposite Film

Thin films of polystyrene and polystyrene-TiO2 nanocomposite were prepared by spin coating from a polystyrene solution in which TiO2 nanoparticles were dispersed by mechanical mixing. Thin films of polystyrene (PS) and polystyrene-TiO2 nanocomposite were exposed to UV irradiation for varied time intervals. The effect of UV radiation on the optical properties, crystallinity, surface energy and degradation of PS-TiO2 nano-composite has been studied. X-Ray diffraction analysis (XRD), UV-Vis and FTIR spectroscopy, Atomic Force Microscopy (AFM) and contact angle measurement were used to study the induced changes of the properties of the irradiated PS-TiO2 nanocomposite. Optical band gaps and hydrophilicity in UV-irradiated samples were altered by destruction processes. The optical band gap values were found to reduce from 4.54 eV in pure PS to 4.45 eV for PS-TiO2 nanocomposite prior to irradiation. This value is further reduced to 3.46 after UV irradiation for 45 h.