Functional-group analysis on a polymer surface by X-ray photoelectron spectroscopy preceded by selective chemical derivatization

Abstract

Numerous studies on surface functional-group analysis by X-ray photoelectron spectroscopy (XPS) preceded by chemical derivatization have been reported. In the present work we established a novel gas-phase chemical-derivatization technique for amine groups. Pentafluorobenzaldehyde (PFBA) has been reported to be a derivatization reagent for primary amine, but trifluoroaceticanhydride ( TFAA ) has been found to be more effective for the amine group. Although TFAA is known to react with primary and secondary amines and hydroxyl groups, we found that the hydroxyl group derivatized by TFAA could be cleaved by exposure to ammonia vapor; on the other hand, the amine group was not. According to this set of preparations, only the amine groups could be selectively modified, even if both the hydroxyl and amine groups existed on the surface. We concluded that this method is superior in chemical reactivity and selectivity for derivatization with PFBA; furthermore, it is available for derivatization of both the primary and secondary amine groups.