ABSTRACT
As described in Chapter 4, the luminous gas stream in the low-temperature cascade arc torch (LPCAT) is unique in that it consists of mainly excited neutral species of argon (Ar as the carrier gas), i.e., the influence of electron and ion bombardment is virtually neglegible. Thus, LPCAT argon treatment would provide a unique opportunity to examine the effect of Ar luminous gas on the surface modification of PTFE. The surface water contact angle changes on the surface modified by LPCAT are shown in Figure 18.9. It can be seen that in LPCAT a high argon flow rate over 1500 sccm is necessary to effectively reduce the surface contact angles of PTFE. In LPCAT, the flow rate of argon is proportional to the number of excited species as long as a sufficient power is supplied, as described in Chapter 16. Results shown in Figure 18.9 follow exactly this dependence.
