Thesis Details

Thesis Title: Surface tension measurements by the oscillating drop method
Thesis Author: Bernard Bornong
Abstract: Methods for measuring the surface tension of pure liquids and solutions are of two main teypes, characterized by the time interval between the formation of the interface and recording the physical property used in calculations: (1) dynamic methods (oscillating drop and vibrating jet) in which the air-liquid interface is usually established in 0.01 to 0.05 second; and (2) static methods (capillary rise, drop weight, ring detachment) in which measurements are made on an interface of age ranging from seconds to hours. The dynamic method used in the experiments reported is based on measurement of the period of oscillation and the weight of falling drops. A high speed motion picture camera, operating at 2000 to 3000 frames per second, was used to record the oscillations. Surface tension measurements were made on distilled water, formamide, aniline, chlorobenzene, and isobutyl alcohol by the oscillating drop method. The values obtained were in good agreement with those given by the capillary rise and ring methods. Solutions of the surface active materials Aerosol OT, Nacconol NRSF, Triton N-100, and sodium oleate were studied by the oscillating drop method and the data compared with those given by the capillary rise and ring methods. The static methods provided lower values for surface tension than the oscillating drop method in the 0.01% to 0.001% concentration range.