Influence of oxygen and argon plasma treatment on wettability and surface morphology of polypropylene microfibers

The surface treatment of polypropylene microfibers by plasma processing in oxygen and argon was studied with the motivation to increase their cohesion with the cement matrix. By plasma treatment, it is possible to modify the surface of the microfibers mechanically, chemically or with a combination of both. The microfibers were modified using the reactive ion etching plasma system. The surface of the microfibers was modified by oxygen and argon plasma. The wettability of the microfibers was measured using the Packed Cell method. Furthermore, the weight of the microfibers before and after plasma modification was measured. Finally, the surface of the modified microfibers was examined by scanning electron microscopy. Almost all modifications of the microfiber surfaces were able to increase their wettability with water. The wettability of the oxygen plasma treated microfibers increased on average by about 11%, the wettability of the argon plasma treated microfibers increased on average by about 6% compared to the fibers without modification. The mechanical effect of plasma treatment was proven only for microfibers modified by oxygen plasma.