Abstract
The formation of solvent-cast, poly(methyl methacrylate) (PMMA) thin films from dilute bromobenzene solutions was studied using an ellipsometry technique. Bromobenzene has a relatively high refractive index (compared to PMMA), which provides contrast in ellipsometry, allowing the concentration to be determined. The solvent also has a relatively low evaporation rate, which makes the film formation slow enough to capture via the technique. The formation of the glassy film is thus studied in situ, and information on solvent and void concentration in the thin film during the film formation process is obtained. There is evidence that nanovoids (representing intramolecular space) develop in the film when solvent evaporates.