Non‐Destructive Sub‐Surface Chemical Characterization of Air‐Exposed Plasma Polymers by Energy‐Resolved XPS

Abstract

Abstract Plasma polymers containing oxygen‐ and nitrogen‐based surface chemistries were prepared from allyl alcohol, allylamine and acrylic acid. Established selective chemical derivatisation procedures with trifluoroacetic anhydride (TFAA) and 4‐trifluoromethyl benzaldehyde (TFBA) were used to determine alcohols and amines, respectively. Samples were analysed by energy‐resolved XPS (ERXPS), enabling XPS depth resolution. We demonstrated that slightly aged plasma polymers prepared from allyl alcohol and allylamine present a homogeneous sub‐surface chemistry within the range of the XPS information depth (≈10 nm); this was clearly not the case for their acrylic acid counterparts. Furthermore, it is shown that standard derivatisation reactions result in homogeneous changes of the chemistry. magnified image