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 (numbers or mole numbers per unit area) of chemical functional groups. Because of the very small thickness dmod of the modified surface region, a simple equation can be applied that allows the calculation of 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 N2 + H2 mixtures, an initial amination rate of about 1 nm-2 · s-1 has been determined.