Optical and structural properties of nanocomposites based on HMW-PMMA reinforced by spherical and rod-shaped titanium dioxide nanoparticles

This work presents an investigation on the optical and structural properties of two series of nanocomposites based on the incorporation of spherical- (NDs) or rod-shaped (NRs) semiconductive crystalline titanium dioxide (TiO2) nanoparticles (NPs) into an insulating amorphous polymethylmethacrylate (PMMA) matrix. The UV-visible absorbance and reflectance measurements reveal that the increase in TiO2 NP concentration within the polymer matrix reduces the forbidden band size for both NDs and NRs, leading to an improvement of the refractive index. SEM and TEM morphological characterizations were performed to investigate the size, size distribution and NPs dispersion within the polymeric matrix. The structural analyses performed by using X-ray diffraction show peaks ascribed to the TiO2 crystalline structure while infrared (FT-IR) spectra indicate the occurrence of interactions between nanofillers and the polymer chain of the host matrix.