Surface Radical Detection on NH₃‐Plasma Treated Polymer Surfaces Using the Radical Scavenger NO

Polystyrene was treated by low‐pressure microwave‐excited ammonia plasmas to generate surface amino groups and subsequently treated with NO to label the remaining carbon radicals for in situ detection by XPS. Short time treatments between 5 ms and 40 s duration were used to vary densities of amino groups and radicals and thus to distinguish different reaction pathways. Apparently, after less than 30 ms treatment no tertiary carbon radicals exist. Also, there are indications that amino groups react with NO to carbon radicals which in turn react with NO. A more detailed study of surface radical generation at very low treatment times would be promising. magnified image