Surface tension determined with a micromethod

✍ Scribed by Pandu Rao; Goran Enhorning

• Book ID: 103968581
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 430 KB
• Volume: 4
• Category: Article
• ISSN: 0927-7765
• DOI: 10.1016/0927-7765(95)01169-j

✦ Synopsis

A modification of the maximum bubble pressure method is described. It allows a convenient determination of surface tension in a small volume of sample (0.5 gl). A specially designed glass capillary has a short, very narrow section (i.d. 0.26 ram) into which the liquid to be studied is instilled. It forms a column of liquid, which blocks the capillary lumen. However, when pressure is slowly raised on one side of the column, the liquid is eventually extruded so that air can get through. Pressure is then seen to drop abruptly from reaching a peak when the meniscus, forced to diminish in size, reaches the most narrow section of the capillary. The peak pressure is proportional to the surface tension and is used to calculate the sample's surface tension. Pure liquids and various concentrations of methanol have been studied, and as an example of a biological liquid that is available in limited quantities only, tear fluid was examined. Its surface tension was found to be 64.3 _+ 0.9 mN m-1 (mean _+ standard error).