Change in charging characteristics of high polymers by plasma treatment

The changes in charging characteristic and contact angle of polyethylene by plasma treatment in argon and oxygen gas were investigated. After the treatment, the samples were found to tend to charge more negatively. Both changes in charging characteristic and contact angle were correlated to each other. In the case of treatment in argon gas, the change is correlated to the input electric energy of plasma. On the contrary, in the case of treatment in oxygen gas, the changes in both characteristics are very abrupt at small input energy region and they soon become small. Though the mechanism of the change in both characteristics are not clear now, generation of hydroxyl groups and carbonyl compound on the surface of high polymers are observed.