X-ray photoelectron spectroscopy (XPS) and Energy-dispersive X-ray spectroscopy (EDS/EDX) are composition characterization techniques that use x-ray excitation of electrons to discrete energy levels to quantify chemical composition. These techniques provide characterization at surface depths of 1–10 nanometers, approximately the range of oxidation in plasma and corona treatments. In addition, these processes offer the benefit of characterizing microscopic variations in surface composition.
In the context of plasma processed polymer surfaces, oxidized surfaces will obviously show a greater oxygen content. Elemental analysis allows for quantitative data to be obtained and used in the analysis of process efficiency.