Effect of Gamma Radiation on the Properties of Poly(Methyl Methacrylate)/Titanium Dioxide Nanocomposite Films

In this study, poly(methyl methacrylate)/titanium dioxide (PMMA/TiO2) nanocomposite films (NFs) were prepared by a solution casting method and afterward irradiated with gamma (γ)-rays at different doses. The structural and optical properties of the PMMA/TiO2 NFs before and after γ-irradiation at different doses were analyzed by X-ray diffraction (XRD) and ultraviolet-visible (UV-vis) spectroscopy, respectively. In addition, the impact of γ-dose on the wetting properties of PMMA/TiO2 was determined by measuring the water contact angle. The XRD patterns illustrated new sharp peaks after the incorporation of TiO2 nanoparticles (NPs) into the PMMA matrix, which could be due to the interaction of TiO2 with PMMA owing to the change in the crystallographic organization. Moreover, the degree of the disorder increases with increasing γ-dose. Optical property studies revealed that the optical gap-band energy of the PMMA/TiO2 dropped to 3.92 eV at the highest γ-dose compared with pure PMMA, which was estimated to be 4.5 eV. A remarkable increase in the number of carbon atoms per cluster was observed with increasing γ-dose. The water contact angle was decreased with increasing γ-dose. The decrease in water contact angle is due to the formation of an oxidized layer and/or carbonaceous clusters on the surface of the γ-irradiated nanocomposite films. Therefore, it can be concluded that PMMA/TiO2 NFs with controlled optical gap-band energy and controlled water contact angle can be prepared by the γ-irradiation technique to be used for the fabrication of optoelectronic products.