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.