Surface treatment of polypropylene films using homogeneous DBD plasma at atmospheric pressure in air

The homogeneous dielectric barrier discharge (DBD) in atmospheric air is most favorable for polymer surface modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing. In this paper, polypropylene (PP) films are treated using a homogeneous DBD plasma in atmospheric air. The surface properties of PP films are studied using contact angle and surface energy measurement, scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR), and the aging effect after treatment when the treated materials are exposed to open air is also studied, with the modification mechanism being discussed. It is demonstrated that non-thermal plasmas generated by homogeneous DBD in atmospheric air is an effective way to enhance the surface properties of PP films. After the plasma treatment, the surface of PP film is etched, and oxygen-containing polar groups are introduced into the surface. These two processes can induce a remarkable decrease in water contact angle and a remarkable increase in surface energy, and the surface properties of PP films are improved accordingly.