Effect of Poly (Methyl Methacrylate) Solute Concentration in Chlorobenzene on the Optical Properties of Films Prepared by Spin Coating

This study addresses the effect of solute concentration on the optical properties of poly(methyl methacrylate) (PMMA) films prepared using the spin-coating technique. The films were fabricated at three concentrations (1.5%, 2% and 2.5%) and examined over a wavelength range )250-900. nm (.The results showed a significant decrease in transmittance with increasing solute concentration, reflecting its impact on absorption characteristics. Furthermore, the optical band gap was determined, showing a decrease from 3.91 eV at a concentration of 1.5% to 3.892 eV at a concentration of 2.5%, indicating a direct relationship between increased solute concentration and a narrowing of the band gap. Other optical constants, including the refractive index, were calculated using models such as the Wemple-DiDomenico and Drude-Lorentz models. These findings highlight the effect of solute concentration on the optical properties of PMMA films, suggesting their potential use in various optical applications.