Improvement of hydrophilicity of polymer film surface using dielectric barrier discharge treatment

To determine the effects of air dielectric barrier discharge (DBD) plasma treatment on the changes of material surface properties for achieving large-scale industrial application of DBD plasma, the surfaces of PET, PP and PTFE films are modified using non-thermal plasma generated by DBD in air, and the effects of DBD plasma treatment on the hydrophilicity of material surfaces are studied. The changes of the water contact angle and surface energy of treated surface with treatment time are studied, and the aging effect after treatment when the treated materials are exposed to open air is also studied. Results show that, the contact angle decreases with the increase of treatment time and the surface energy increases with the increase of treatment time, and both of them achieve the saturated value at certain treatment time, indicating that there exists an optimum parameter for the surface treatment. After long-term storage in ambient air, it is found that the much lower surface water contact angle of the processed polymer films partially recovers but the value of water contact angle is still much lower than that of the untreated materials even after 12 days storage. This reveals that the treated polymer surfaces have a good stability over aging time.