Studies of Water-in-Oil Emulsions: Stability Classes and Measurement

摘要

The paper summarizes studies to determine the stability of water-in-oil emulsions and the measurement of emulsion stability. The most important question related to emulsion analysis is whether they are stable. In the strict thermodynamic sense, all emulsions are unstable; however, experimental evidence has shown that some emulsions with persist over a matter of months. A commonly-accepted definition is that an emulsion is considered stable if it persists at least five days at 15 degrees C. An assessment of several tests of stability has been correlated to the basic definition. These tests include: observation of the colour of the emulsion, viscosity, elasticity, zero-shear rate viscosity, water content, and conductivity. The latter two measures are not, in themselves, reliable indicators of emulsion stability.