Processing and characterisation of polystyrene coatings and free-standing plates

In this study, polystyrene (PS) coatings were prepared on quartz substrates by using a dip coating method. The refractive index, dispersion, and thickness of the coatings were determined using an extended Swanepoel's method. This method accounted for coatings coated on the front and back sides of the substrate and thickness variation across the coating. By adjusting the solution's molarity, the substrate's rate of withdrawal, and the number of coating process iterations, the impact on the coating's thickness was investigated. These findings were used to create an empirical model that allowed the thickness of the final coatings to be calculated using the experimental parameters. A quartz slide (49 mm × 49 mm x 1 mm) was coated with a 6.1 (±0.2) μm layer of PS. The thickness was verified using an independent method which demonstrated the validity of the empirical relation. Free-standing PS plates were also produced and characterised. These plates were made utilising a purposely made cast using the solution casting method. The PS samples produced have high transmittance in the UV, visible, and near-infrared wavelength ranges with an average absorption coefficient of 1.7 ± 0.9 cm⁻¹. Because of this, they are well suited for use in some optical applications.