Tuning optical and structural properties of polystyrene nanocomposites with rutile TiO₂ nanoparticles

The surface morphology and structural properties of polystyrene (PS)/TiO₂ nanocomposites were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), while optical properties were assessed via UV-Vis spectroscopy and Fluorescence measurements. SEM images revealed uniform dispersion of TiO₂ nanoparticles with sizes ranging from 48 to 58.5 nm in the PS matrix, showing no significant agglomeration. XRD analysis revealed a decrease in crystallite size with increasing TiO₂ concentration. UV-Vis spectra demonstrated a decrease in the band gap with increasing TiO₂ concentration, indicating a shift towards enhanced visible light absorption. PL spectra excited at 330 nm revealed distinct emission peaks, with significant increases in intensity at higher TiO₂ concentrations, particularly at 399 nm and 422.5 nm, corresponding to near-band-edge and defect-related emissions. FTIR analysis demonstrated that the incorporation of TiO₂ led to disruption of C-O bonds in the PS matrix, particularly at 10% TiO₂, suggesting strong interactions between the TiO₂ nanoparticles and the polymer, which may weaken the polymer backbone. Overall, these findings suggest that TiO₂ incorporation not only impacts crystallite size and strain but also enhances the optical and fluorescence properties of PS/TiO₂ nanocomposites.