Surface modification of polymers by a nanosecond-pulse plasma jet

Cold atmospheric-pressure plasma is rich in active particles, with good physical and chemical properties. It has a wide range of applications in areas such as surface modification of materials, and biomedical and environmental treatment. A dielectric barrier discharge is a traditional way to generate cold plasma, but its confined discharge gap limits some applications. The plasma jet is a method to produce plasma beyond the plasma generation region, and has a relatively simple electrode structure. It can be applied in a narrow space and on complex surfaces. In this paper, a single needle electrode is used to generate a plasma jet that is driven by unipolar repetitive nanosecond pulses with rise time of 25 ns and a full width at half maximum of 40 ns. The characteristics under different experimental conditions are observed. On the basis of previous work, film surfaces of polyethylene terephthalate and polymethylmethacrylate are modified, and hydrophilic and hydrophobic results are achieved correspondingly.