Heating effects on modifying carbon surface by reactive plasma

In the surface modification by plasma, surface properties changes with time after the plasma treatment. Such changes should be avoided for practical application. Glassy carbon (GC) was subjected to simultaneous plasma and heat treatments in order to investigate the respective effects. Source gases were tetrafluoromethane (CF4) and oxygen (O2). Treatment time and heating temperature of the GC plate were 30 min and 200–500°C, respectively. The surface properties before and after plasma treatment were studied with contact angle measurements and ESCA. When the GC was heated at 400°C during CF4 plasma treatment, the contact angle after plasma treatment was 133° and constant even after 24 h. At 500°C during O2 plasma treatment, the contact angle after plasma treatment was 0° and constant even after 24 h. It is found that heating carbon surface during CF4 or O2 plasma treatment is effective to stop the change with time after plasma treatment.