What is the principle of emulsification?

Under the action of ultrasonic energy, two or more immiscible liquids are mixed together, and one of the liquids is relatively uniformly dispersed in the other liquid to form an emulsion-like liquid. This process is called ultrasonic emulsification.

Phacoemulsification is caused by the phenomenon of cavitation. Ultrasonic waves passing through the liquid cause it to compress and expand continuously. High-intensity ultrasonic waves provide the energy needed to disperse the liquid phase. When the maximum pressure is reached, at the point of weaker cohesion, a liquid rupture occurs. After this rupture, overpressure occurred at the point of rupture and some cavities were found. In these cavities, the liquid dissolved gas explodes after a short time in the form of bubbles.

To stabilize the newly formed dispersed phase droplets against coalescence, emulsifiers (surfactants, surfactants) and stabilizers are added to the emulsion. The final droplet size distribution was maintained at the same level as when the droplets were distributed after breakup in the ultrasonic dispersion zone.

The cavitation process is affected by the frequency and intensity of ultrasonic waves, and the appearance of cavitation in the body is largely dependent on the presence of undissolved gas suspended in the liquid, which seems to act as a catalyst. At a certain pressure, the formation of the cavity depends to some extent on the development time and the ultrasonic frequency. The phacoemulsification process represents a competition between opposing processes. Therefore, it is necessary to select suitable operating conditions and frequencies so that the destruction effect dominates.

Ultrasonic cavitation effect

To prepare oil-in-water emulsions, the ultimate sound intensity is much lower than that for preparing water-in-oil emulsions. The type of sound field affects the emulsification process, ie a certain traveling wave is applied. Compared to applying some stationary waves, the process efficiency is improved. This can be explained by the fact that in a stationary wavefield, the opposite process to dispersion, condensation, predominates.