Emulsifiers
Emulsifier is one of the most commonly used and most versatile surfactants in daily life. It is a typical amphiphilic compound with a polar or hydrophilic (i.e. water-soluble) part and a non-polar (i.e. hydrophobic or lipophilic) part. It is mainly used in food, pharmaceuticals, hair styling, personal hygiene and cosmetics.
In the daily chemical industry, in addition to adding ingredients, additives are also needed to stabilize the product state during the research and development of cosmetics and washing. Among them, emulsifiers are one of the important components of cosmetic raw materials. They play the role of emulsification, dispersion, solubilization, lubrication, softening, stabilization, etc., so that one of the two immiscible liquids can be evenly dispersed in the other liquid. It can be said that without emulsifiers, most formulas cannot exist, and many active ingredients cannot be added to the formula. Therefore, the use of emulsifiers and even the correct, precise and scientific use of emulsifiers is the basis for formulation engineers and is indispensable.
Cosmetic Formula Solutions: Emulsifier Selection and Formula Design
In cosmetic formulations, the selection of emulsifiers needs to consider the following factors:
- Emulsion type: oil-in-water (O/W) or water-in-oil (W/O).
- Formula ingredients: the ratio of oil phase and water phase, the nature of active ingredients.
- Target skin feel: refreshing, moisturizing or heavy.
- Safety: whether it is suitable for sensitive skin or specific skin types.
Case Study: Innovative Emulsifiers in Cosmetics
(Cortes, Natalia, et al. 2024)
Natalia Cortes et al. investigated the patented cosmetic emulsifiers from 2013 to 2023, involving a total of 51 patents. The development of new cosmetic emulsifiers focuses on integrating natural compounds into formulations and using the synergistic effects of different compounds to produce better emulsified compositions.
Emulsifiers are classified according to the number and type of compounds they contain, and the results are shown in the figure. Among them, the only example of a single compound emulsifier is modified titanium dioxide. This modified titanium dioxide can produce greater amphiphilicity and dispersibility in emulsions, and improves stability by increasing the contact angle from the original 50° to 83.3±3°. Other interesting emulsifiers are emulsifiers obtained by microorganisms, involving a microorganism: Candida bombicola.