The words, "hydrophobic" and "hydrophilic" are used in common everyday language as well as in technical publications; in fact, one of them is used in the title of this abstract. Scientists and other technical personnel often try to quantify surface properties using these words, sometimes with prefixes such as "super", "ultra", or even "perfectly." They are generally not successful in their quantifiction. Several topics will be presented in this talk that may include: (1) A discussion about water and its aggregation state in different media and at interfaces, (2) The evaporation/condensation equilibrium and how topographic features near to but on either side of the Concus-Finn Inequality can drive the equilibrium in either direction, (3) An alternative explanation of the "Cheerios Effect" that uses floating objects of variable density that do not exhibit liquid/solid/vapor contact lines, (4) Water drops "hopping" from and "bouncing" off surfaces that contain defects of controlled size, shape and orientation (Figure 1a shows a frame from a high speed videotape recording of a drop that has reflected from a surface containing two defects), (5) The sorption and permeation of water into and through the "hydrophobic" material, PDMS. Figure 1b shows a photograph of two membrane-capped (exact same composition, but different thickness) vials at the same temperature.

Water and its motion onto, across, off of, out from between, and through hydrophobic materials

254th National Meeting (2017)

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