The Principle And Application Of Ultrasonic Emulsification

Ultrasonic emulsification refers to the process of mixing two (or more) immiscible liquids under the action of ultrasonic energy to form a dispersed system, where one liquid is evenly distributed in the other liquid and forms an emulsion.
Compared with general emulsification processes and equipment such as propellers, colloid mills, and homogenizers, ultrasonic emulsification has the characteristics of high emulsification quality, stable emulsification, stable emulsification products, and low required power.

The principle of ultrasonic emulsification

The physical mechanism of crushing insoluble solids (or liquids) is believed to be ultrasonic cavitation. Ultrasonic cavitation effect refers to the generation of a large number of bubbles in a liquid under the action of strong ultrasound. Small bubbles will gradually grow and increase with ultrasonic vibration, then suddenly burst and split, and the split bubbles will continue to grow and burst. When these small bubbles collapse rapidly, they generate high temperature and pressure inside the bubbles, and strong local shock waves are generated in the liquid near the bubbles due to the high-speed impact of the liquid around the bubbles, which also forms local high temperature and pressure, resulting in ultrasonic crushing and emulsification.

Industrial applications of ultrasonic emulsification

In the pharmaceutical and daily necessities industries, ultrasonic emulsification is commonly used to manufacture various emulsion products, such as emulsion drugs, cosmetics, and shoe polish. Ultrasonic emulsification can also be used to produce emulsified combustibles of oil (gasoline, diesel, etc.) with water or coal powder, in order to improve the combustion value per unit of fuel.
This technology has now been promoted and used within a limited range, with significant economic benefits. In order to reduce costs and adapt to large-scale production, mechanical ultrasonic transducers such as reed whistles are mostly used in ultrasonic emulsification. For liquids that are difficult to emulsify or for other special considerations, piezoelectric ultrasonic transducers are sometimes used in conjunction with appropriate sound focusing systems to increase sound intensity.

Medical applications of phacoemulsification

Treating cataracts

Using a phacoemulsifier, through a corneal or scleral incision of 3-5mm in size, the lens nucleus is crushed with ultrasound to form a chyle shape, and then sucked out together with the cortex. After surgery, the posterior capsule of the lens can be preserved and a posterior chamber intraocular lens can be implanted simultaneously.
Compared with traditional cataract surgery, phacoemulsification has better surgical results and has become the most reliable method for cataract treatment.