Effect of silicon powder on the optical characterization of Poly(methyl methacrylate) polymer composites

The polymer composite films of Poly(methyl methacrylate) (PMMA) doped with different wt% of Silicon powder (Si) were prepared using solution casting technique, to investigate the effect of Si content on the optical characterization of PMMA matrix. It is found that the fundamental optical absorption edge of PMMA is shifting toward lower energy with the increase of the Si content, resulting the decreases in the optical band gap of PMMA monotonously. The optical constants of PMMA:Si composite, such as the optical absorption coefficient, refractive index, extinction coefficient and complex dielectric constant, are greater than those of pure PMMA. The energy dispersion parameters of PMMA:Si composite versus Si wt% have been determined and explained using Wemple-DiDomenico single oscillator model. The linear relationship between the static refractive index and Si volume fraction reveal the well-dispersed Si powder in the PMMA host polymer matrix. The SEM micrographs also revealed the uniform dispersion of Si powder in PMMA matrix. The observed improve in the optical properties of PMMA:Si films denote that this composite could be used in UV-blocking contact lenses and optoelectronic devices.