What does emulsification look like!

Emulsification is the effect of a liquid being uniformly dispersed in another liquid that is immiscible with very small droplets. Emulsification is a liquid-liquid interface phenomenon. Two immiscible liquids, such as oil and water, are divided into two layers in a container, a low density oil is in the upper layer, and a dense water is in the lower layer. If a suitable surfactant is added, the oil is dispersed in water under strong agitation to form an emulsion, which is called emulsification. Two mutually immiscible liquids, one in which particles (droplets or liquid crystals) are dispersed in another, are called emulsions. This system is thermodynamically unstable due to the increased boundary area of ​​the two liquids when forming the emulsion. In order to stabilize the emulsion, a third component-emulsifier is added to reduce the interfacial energy of the system. Emulsifiers are a surfactant whose typical function is to act as an emulsifier. The phase in which the droplets are formed in the emulsion is called the dispersed phase, or the inner phase or the discontinuous phase; the other phase that is connected in one piece is called the dispersion medium, or the outer phase, the continuous phase. Emulsions are the most widely used form of cosmetics, from watery fluids to viscous creams. Therefore, the discussion of emulsions is extremely important for the research and production of cosmetics, as well as for preservation and use.

What does emulsification have?

Emulsification refers to the process of emulsification of incompatible oil and water to form a relatively stable emulsion [1]. Most of the emulsifiers used to form the emulsion are surfactants, which consist of a hydrophilic group and a hydrophobic base, which form a film at the oil/water interface to reduce the surface tension. In the above process, the presence of the surfactant causes the non-polar hydrophobic oil droplets to become charged colloidal particles, increasing the surface area and surface energy. Due to the polarity and surface energy, the charged oil droplets adsorb the counter ions or polar water molecules in the water to form a colloidal electric double layer, preventing the oil droplets from colliding with each other, so that the oil droplets can stably exist in the water for a long time.

Emulsions can be classified into oil-in-water (O/W), water-in-oil (W/O) and multiple emulsions. The emulsion in which the internal phase is the outer phase of the oil is the W/O emulsion; the emulsion in which the oil is the outer phase of the oil is the O/W emulsion. There are also two types of multiple emulsions, W/O/W and O/W/O. The W/O/W type is an oil phase containing dispersed water droplets suspended in the aqueous phase, and the O/W/O type is an aqueous phase containing dispersed oil beads suspended in the oil phase. Multiple emulsions were discovered as early as 1925, but it was not applied until 1965.

What is the emulsification of skin care products?