Electrostatic stability, measurement emulsion systems

Figure 11. Schematic representation of the electrophoretic mobility (A) measurement showing the major components. In an applied electric field, emulsion droplets move according to their surface charge. These charges can electrostatically stabilize an emulsion system by preventing the droplets from coming into contact and coalescing. The motion of the droplets is visually observed, and the electrophoretic mobilities of a number of particles are measured to determine zeta potential. The sedimentation potential (B) is also illustrated.

Electrokinetics. Bottle tests and centrifugation may be somewhat crude, but they do offer a relative measure of emulsion stability that combines, to some extent, all of the factors that affect stability. Electrokinetic measurements are somewhat more elegant because they allow direct measurement of the degree of electrostatic stability in an emulsion system. The zeta potential, or relative magnitude of the electric charge on the surface, is... 

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