Heating Effects of Carbon Material in Modifying its Surface with Tetrafluoromethane Plasma

Abstract

We discussed heating effects of carbon material in modifying its surface with tetrafluo-romethane (CF4) plasma. The contact angle of water on the carbon material surfaces before and after the plasma treatment was measured to estimate the modification effects by plasma and their change with elapsed time was investigated. The carbon material surfaces were observed by scanning electon microscopy. From these results, the following conclusions could be drawn.The elapsed change of the surface contact angle on the glassy carbon could be extremely minimized by heating its carbon at 400°C in modifying it by CF4 plasma. This may cause due to the introduction of only the covalent bond type fluorine, which is insoluble in water, stable to heat and difficult to secede from the surface, by heating the glassy carbon at 400°C when it was treated by CF4 plasma. It was seen that the value of the contact angle at 10 minutes after CF4 plasma treatment in heating it was almost constant, which is about 130°, even if the heating temperature varied from 0°C to 400°C. The surface morphology of the glassy carbon treated by CF4 plasma as it was heated, was revealed to become a little more sharp and irregular by etching in comparison with that of the glassy carbon treated by CF4 plasma without heating it.