Approaches to quantify amine groups in the presence of hydroxyl functional groups in plasma polymerized thin films

The quantification of primary and secondary amines in plasma polymerized allylamine and plasma copolymers of allylamine/octadiene films was carried out using chemical derivatization followed by X-ray photoelectron spectroscopy. Data was analyzed using a combination of the peak-fit-analysis method (PFA) and the quantitative-elemental-analysis method (QEA). The latter method overestimates the secondary amine contribution, since it does not account for the additional reaction of TFAA with OH groups that may be present as a result of surface aging effects. In the current work the PFA method has been extended to enable the separation of -OH groups and secondary amines, thus allowing for a more precise determination of the secondary amine groups even after surface aging.