Research on Physical Properties and Internal Structure of PVP/Nb₂O₅ Nanocomposite Coatings

The subject of this study are thin films of poly(N-vinylpyrrolidone) (PVP) and its composites with niobium pentoxide nanoparticles (Nb₂O₅/NPs), with varying nanoparticle concentrations. The obtained results indicate that the addition of nanoparticles significantly affects the physical properties of the investigated materials, limiting their optical UV transmittance in the range of 300-500 nm and increasing the material's resistance to moisture, which is present in the surrounding environment. Based on our thermal measurements, performed using differential scanning calorimetry (DSC) and variable temperature spectroscopic ellipsometry (VASE), as well as the results obtained using scanning electron microscopy (SEM), we can indicate that an interfacial surface with a changed polymer chain mobility is formed between the Nb₂O₅ nanoparticles and the polymer matrix, as evidenced by the appearance of an additional, intermediate glass transition temperature, visible in the ellipsometric temperature cycles. This is closely related to the formation of surface clusters resulting from the agglomeration of Nb2O5 nanoparticles. The results indicate that the investigated composite coatings could be employed as surface coverings to protect against external, environmental influences, like the moisture and UV radiation