Solidified sessile drop

Thus, measurements of solidified sessile drops can be and are used to derive estimated values of contact angles, but these estimates are less precise than those derived from direct observation of liquid drop profiles except for very well wetting systems. The estimates for solidified drops tend to be smaller, typically by up to 5°, and more variable than those derived from observation of liquid profiles. Larger differences can be observed when, during cooling, dewetting of the liquid drop occurs before the resolidification temperature is reached. In this case, traces of the location of the triple line before dewetting are easily seen on the substrate surface. 

Figure 10.8. The room-temperature tensile strengths of solidified sessile drop interfaces formed between AI2O3 and Cu-Ti alloys plotted as a function of the Ti concentration, (Nicholas 1986).

Table II presents the results of some wettability measurements on adsorbed monolayers prepared from molten Compound D on pure, polished, clean, chromium surfaces after solvent treatment had been used to remove all surplus solidified acid. A series of successive solvent treatments was applied to each coated specimen (see first four columns of Table II) using liquids which have been shown to be good solvents for Compound in the bulk (9). These liquids were either absolute ethyl alcohol or benzene at or above 20°C., or n-hexane at or above 60°C. In the remaining columns are listed the average values of the slowly advancing contact angles measured by the drop-buildup method on from three to five different drops. Measurements were made on sessile drops of water, thiodiglycol, and methylene iodide. These three diagnostic liquids were chosen because of their high surface tensions (72.8, 54.0,...

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