Critical remarks on chemical derivatization analysis of plasma‐treated polymer surfaces and plasma polymers

The notion that individual functional groups on plasma‐modified polymer surfaces or in plasma polymers can be detected and quantified using selectively reacting derivatization reagents has dominated the field of plasma‐based surface technology since more than 30 years. For nitrogenated films and surfaces it has traditionally been believed that amino groups can be analyzed selectively using electrophilic reagents such as benzaldehydes or carboxylic acid anhydrides. This article presents arguments indicating that traditionally applied methodologies are partially based on myths. Presumed amino groups are – at least to a substantial extent – probably in fact other nitrogen‐bearing moieties. It is open to question if primary or secondary amino groups could “survive” the physico‐chemical environment typical of a plasma at all. Advancing the chemical understanding of N‐containing plasma‐generated films and surfaces, and plasma‐chemical formation mechanisms requires rethinking the interpretation of derivatization experiments.