THE LINE/PSEUDO-LINE TENSION IN THREE-PHASE SYSTEMS
DRELICH, JAROSLAW; MILLER, JAN D.; DRELICH, JAROSLAW; Department of Metallurgical Engineering, University of Utah; MILLER, JAN D.; Department of Metallurgical Engineering, University of Utah
Журнал:
Particulate Science and Technology
Дата:
1992
Аннотация:
ABSTRACTThe effect of drop (bubble) size on contact angle was examined over a wide range of drop (bubble) sizes for the CCl<sub>4</sub>-toluene solution/NaCl aqueous solution/quartz, ethylene gtycol/CCI<sub>4</sub>-toluene solution/quartz, bitumen/ Na<sub>5</sub>P<sub>3</sub>O<sub>10</sub> aqueous solution/quartz, water/kerosene/quartz, heptane/water/quartz, and air bubble/water/polyethylene systems. For most systems, a nonlinear relationship between cosine of the contact angle and reciprocal of drop (bubble) base radius was obtained. All known factors affecting the contact angle/drop size relationship are discussed. It was found that the effect of gravitational forces as well as solid strain in the vicinity of the three-phase contact line are not responsible for the contact angle/drop size relationship for the systems examined. It appears that surface heterogeneities (contaminants) have the greatest effect on the contact angle/drop size relationship as is evident for these results from our laboratory. Also, surface roughness can contribute to the effect of drop size on contact angle. A theoretical background is presented and modifications of both the Cassie Equation and Wenzel Equation are derived.A linear correlation of cosine of the contact angle vs. reciprocal of drop base radius was obtained for the heptane/waler/quartz systems, when high purity single-component liquids and a smooth, chemically cleaned, quartz plate were used. The line tension was determined for this system to be (5.1 ± 4.3) 10<sup> − 9</sup>N.
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