Variation of optical parameters of physically stacked polyvinylidene chloride films with thickness and wavelength

A study of thickness variation and the wavelength dispersion of optical parameters for thin physically stacked films of polyvinylidene chloride (PVDC), namely, refractive index, skin depth and dielectric constant have been performed. The refractive index and dielectric constant of these PVDC films initially increases with increasing film thickness, but for film thickness greater than 0.0048 cm, it is observed that these parameters vary with thickness to a much lesser extent, but continues to vary significantly with wavelength. The observations are discussed in terms of variation of average values of these optical parameters, along with errors estimated from residual analysis. The variation of these parameters with wavelength of electromagnetic radiation in the visible region (varying from 400 nm up to 700 nm) is presented and discussed. The analysis of the UV–visible spectra revealed the existence of both direct and indirect electronic transitions in k-space by the absorption of photons of suitable energy. The optical band gap depends on the thickness of the films, and there are significant changes in all other optical parameters of PVDC films with both thickness of the stacked films and wavelength of the incident UV-Visible radiation. © 2023