Different patterns of drop size dependence of contact angles have been observed experimentally. Some investigators reported a decrease of contact angle with an increase in drop size, while others reported an increase. Still others reported that there is no drop size dependence of contact angles. The
Effect of Surface Roughness on the Dependence of Contact Angles on Drop Size
โ Scribed by F.Y.H. Lin; D. Li; A.W. Neumann
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 506 KB
- Volume
- 159
- Category
- Article
- ISSN
- 0021-9797
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โฆ Synopsis
Absence of drop size dependence of contact angles of sessile drop systems is sometimes observed in experiments. The contact angle data sometimes fluctuate periodically about a horizontal line. Moreover, in cases where a drop size dependence of contact angles exists, the contact angle data often scatter significantly. These fluctuations may be caused by surface roughness. In this paper, two idealized rough surface models are developed. The mean contact angle of a sessile drop in each rough solid surface model is calculated. The fluctuations of the drop size dependence of contact angles produced by these models resemble those obtained experimentally and the fluctuations may therefore be a conseducence of the roughness on solid surfices. II is also concluded that the apparent absence of drop size dependence of contact angles does not necessarily imply zero or extremely low line tension. (1) 199.3 Acatlennic Press. Inc.
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