Treatment of Polyethylene Terephthalate using low-temperature atmospheric pressure helium plasma jet for improvement of adhesion

A treatment using low-temperature atmospheric pressure plasmas can control the surface properties of materials. In this study, Polyethylene Terephthalate (PET) films were treated by helium plasma jet to improve adhesion between the films. To investigate a role of reactive species on the change of surface property a chamber was used, where argon, dry air, and ambient air were used as surrounding gas. By the plasma treatment for 60s, the contact angle of water on the PET surface was decreased from 82 to 25, 22, and 11 deg. using ambient air, dry air, and argon as surrounding gas, respectively. To observe the effect of plasma treatment on adhesion between the PET films (0.2 mm thick), a standard T-peel test was carried out. On PET films of 15 mm × 90 mm, the plasma treatments were applied for 60 s. The effective plasma-treated area was about 5 mm in radius. After the plasma treatments, the plasma-treated PET films were pressed with their irradiated surfaces faced under a pressure of 83.3 kg/cm² at 100 °C for 60 s. Using argon as ambient gas, the highest peel strength over 20 N was obtained. In the conference, surface property and morphology of films treated in different ambient conditions will be discussed.