Surfactants are widely used in the cosmetics industry and are important excipients in cosmetics. They have the functions of emulsifying, washing, foaming, solubilizing, etc., and can be seen in daily facial cleanser, moisturizing lotion, skin cream, hair conditioner and other products. This article will introduce you to surfactants and their effects.
1.Chemical structure of surfactants
Surfactant is a bimolecular structure, one end is a hydrophilic polar group, and the other end is an oil-philic non-polar group, which makes it amphiphilic. Surfactants can change the interface state of the solution by relying on their own amphiphilicity, so that insoluble substances can dissolve each other, and can also be combined with different substances to achieve the mutual separation of the original integrated substances. It is this special two-group structure that determines the various functions of surfactants.
2.The role of surfactants
Under normal circumstances, oil and water do not dissolve each other in a layered state, because a stable and uniform dispersion system cannot be achieved, and the oily components and water in such emulsion products as creams and emulsions can form a mixed and uniform dispersion system because of the addition of surfactants. The two group structure of the surfactant makes the non-soluble oil and water two kinds of substances uniformly mixed together to form a relatively stable dispersion system, that is, the emulsion, the surfactant plays the role of emulsification in the emulsion, and the surfactant that plays the emulsification role is called emulsifier.
Our daily use of cream, emulsion skin care products because of the addition of emulsifier to form a mixed and uniform dispersion system, that is, oily ingredients in the form of tiny droplets evenly dispersed in water, or water in the form of tiny droplets evenly dispersed in oily ingredients, the former we call oil in water, the latter is called oil in water, this type of cosmetics we call emulsion cosmetics. It is also one of the most common types of cosmetics.
2. Washing and foaming
Some surfactants have a good washing and foaming effect, facial cleanser is through which soap ingredients (surfactants) play a cleaning role, but soap ingredients cleaning power is strong, easy to cause skin degreasing, and irritation is slightly stronger, so dry skin and sensitive skin should not use this kind of cleansing products. In addition, surfactants are used in products such as bath liquids, shampoos, hand sanitizers and toothpastes for cleaning and foaming.
Surfactants can increase the solubility of some insoluble or insoluble substances in water, so that they are completely dissolved in water, and eventually form a transparent state, this role is called solubilization, and the surfactant that plays the solubilization role is called solubilization. For example, if you want to add a good moisturizing oily component to the transparent toner, but the oil can not be dissolved in water, at this time, you can use the solubilization effect of surfactants, by adding surfactants to make the oily component well dissolved in the toner, the product finally presents a good transparent appearance.
3.The type of surfactants.
1. Sort by structure
Surfactants can be divided into anionic, cationic, zwitterionic and non-ionic types according to their structural characteristics. Among them, anionic surfactants have better washing and foaming effects, and are mostly used in cleaning products. Cationic surfactants have good bactericidal, antistatic and hair softening effects, and are often used in hair conditioners. Zwitterionic surfactants have weak washing effect, but good foaming, foam stabilization and thickening effect. They are often used as auxiliary anionic surfactants in cleaning products to enhance the cleaning effect of products and reduce irritation. Non-ionic surfactants are good at emulsification and solubilization, and have low irritability. They are mostly used in creams, emulsions and water-based products that need solubilization.
2. Green cosmetic surfactant
With the rapid reduction of non-renewable energy such as oil and natural gas, and people's higher requirements for the safety of cosmetics directly in contact with human skin, the green development of surfactants has become the mainstream trend, that is, biosurfactants and biosurfactants. Biosurfactants are usually prepared by yeast or bacteria, which contain glycolipids, chitosan, phospholipids and other types. Now common amino acid facial cleanser is the use of amino acid biosurfactants, which is non-toxic, harmless, and biodegradable. It is believed that green cosmetic surfactants will play an important role in the future cosmetics market.