Contact angle change, thermally

In DC discharge plasmas, the sudden decrease of contact angle after 15 min treatment has been assigned by S. Okasaki et al. to a structural change of the material surface from crystallised graphite to an amorphous state [93]. It has been shown that the fluorination of PAN-based carbon fibers is more effective in the case of CF4-He plasmas than in 5% F2—He plasmas [94]. The study of the thermal stability of these F-treated fibers has shown however that a 70% loss of fluorine occurred when the samples were heated at 293°C for 10 min. 

The study of evaporating rivulet flow shows that macroscopic flow and heat transfer may be considerably changed itself by microscopic heat transfer, the example is establishing of thermal apparent contact angle in case of rivulet evaporation. Extremely high evaporation rate in thin film area changes the slope of interface as far as macro flow curvature and wave patterns. NOMENCLATURE... 

Figure 9-26. Increase of wettability and relevant change of the contact angle as a result of surface treatment by non-thermal atmospheric plasma.

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