Uniformity analysis of atmospheric pressure plasma jet treated ultra-high Molecular Weight polyethylene fiber surface

A new plasma jet, operating in helium/oxygen at atmospheric pressure (APPJ), has been used to induce changes in the surface properties of ultra-high Molecular Weight polyethylene (UHMWPE) fibers. Plasma jet works in an open system in which plasma is produced between capacitively coupled electrodes and then ejected from nozzle to form plasma jet. There is only some part of substrate surface directly contacted with plasma jet at atmospheric pressure while in dielectric barrier discharge plasma surfaces of substrate are all contacted with plasma. Therefore in this study, UHMWPE filament tows were used as the model system to investigate the uniformity of atmospheric pressure plasma jet surface modification in terms of morphology, roughness, chemical composition, and wettability of the fiber surface, as well as the interfacial shear strength of the fiber to epoxy, using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle test micro-bond test. It was concluded that APPJ can homogenously treat each single fiber in filament tow. And longer treatment time and higher output power induced more uniform and greater changes in the surface properties.