EFFECTS OF SURFACE-ACTIVE AGENTS ON DROP SIZE IN LIQUID LIQUID-SYSTEMS

Extensive new experimental data were obtained on the effects of various surface-active agents (SAA) on the size of drops formed at a nozzle tip in liquid-liquid systems. Drop formation times were 0.5-4 s. Of the many relationships for predicting the size of such drops under SAA-free conditions, only a few may be described as even semitheoretical. Of these, the Scheele and Meister equation, representative of the so-called two-stage model, was selected to test the proposition that use of the diminished interfacial tension due to SAA would be sufficient to cause the equation to predict drop size in SAA-contaminated systems. (This simple approach fails with certain other droplet phenomena). When so applied, the equation predicted 772 drop volumes, measured in the presence of SAA, with a mean deviation of only 1.8%, thus running almost through the middle of the data points. Various minor trends are identified. © 1990, American Chemical Society. All rights reserved.