AbstractThe surface modification of a commercial polyethylene fiber treated in an oxygen low temperature microwave plasma was investigated. The change in surface chemistry was analyzed with electron spectroscopy for chemical analysis. A controlled state of oxidation of the fiber surface was reached by variation of gas flux, process pressure and microwave energy. The oxygen was incorporated into the fiber surface in the form of functional groups. In the determined treatment range, a change in surface morphology as a result of the plasma treatment was not observed with electron microscopy. The higher oxygen content in the fiber surface increased the fiber‐matrix adhesion as shown by mechanical test