Abstract
An optical method, i.e. the technique of attenuated total reflection (ATR), has been used for the investigation of the adsorption of poly(methyl methacrylate) (PMMA) and polystyrene (PS) on to a silver surface. This provides a simple and very sensitive method for following the adsorption process and for effecting measurements in situ and in real time. It can be applied to any type of solution and substrate and also to scattering solutions.
The experimental data arising from ATR can be used to calculate the effective thickness d and the complex optical constant ∊ = ∊r + i∊i for the adsorbed polymer film on the Ag surface. By use of the Lorentz–Lorenz relationship, the adsorbance (the amount adsorbed per unit area) was calculated from the effective thickness d and the refractive index of the adsorbed film.
The adsorbance of the polymer (PMMA, PS) with different molecular weights and different solvents has been measured against time. The results satisfy the Langmuir equation more closely than hitherto.
Get full access to this article
View all access options for this article.