Quantitative ATR FT-IR analysis of chemically derivatized plasma-modified polymer surfaces

The quantitative evaluation of ATR FT-IR spectra of chemically derivatized plasma-modified polymer surfaces is proposed in order to derive area densities rho (numbers or mole numbers per unit area) of chemical functional groups. Because of the very small thickness d(mod)) of the modified surface region, a simple equation can be applied that allows the calculation of rho from band area measurements on polymer samples and on suitable reference solutions that contain small molecules with the same functional groups. Applying this method to polymer surfaces plasma aminated in atmospheric-pressure afterglows of N-2 + H-2 mixtures, an rate of about 1 nm(-2).s(-1) has been determined.