Study of the effect of the duration of the cold plasma treatment on the triboelectric properties of polymers

Square plates of Polypropylene (PP), dimensions 100 mm × 100 mm × 4.5 mm were treated by atmospheric Dielectric Barrier Discharge (DBD) generated between two disk-type electrodes (Ø 75 mm), energized from an AC amplifier 30 kV, 20 mA. The study aimed at evaluating the factors that affect the roughness of the plasma treated samples. The alteration of surface aspect after each treatment was clearly visible with the naked eye, and the changes were confirmed by measurements carried out with a portable roughness meter (Surftest SJ-210) and a digital microscope (Keyence VHX-7000). (. The roughness of the PP samples increased from Ra = 0.06 µm and Rq = 0.08 µm to as much as Ra =0.245 µm and Rq = 0.308 µm. These increases were highly dependent on the inter-electrode distance (10.5 to 13.5 mm), the treatment time (5 to 20 min), and the configuration of the DBD cell, i.e. the number (one or two) and the thickness (4 mm or 5 mm) of the glass dielectric barriers.