The role of surfactants in cosmetics

Surfactant is a substance with a very special chemical structure. It is widely used in the cosmetics industry. It is an auxiliary raw material in cosmetic raw materials. Although the amount is not large, it plays a great role. Skin creams, shampoos, conditioners, toothpastes and other products are used in most products. Its functions in cosmetics are diverse, the main functions are: emulsification, washing, foaming, solubilization, sterilization, antistatic, dispersion, etc. Here we introduce in detail its four main functions.

(1) Emulsification

What is emulsification? As we all know, our most commonly used creams and lotions in skin care products contain both oily ingredients and a large amount of Water. They are a mixture of oily ingredients and water. But why do we not see it under the naked eye? Even the oil droplets inside can not see the oozing water? This is because they have formed a very uniformly mixed dispersion system, that is, oily ingredients are evenly dispersed in water in the form of tiny droplets, or water is evenly dispersed in the oily ingredients in the form of tiny droplets. The former is called Oil-in-water, the latter is called water-in-oil, this type of cosmetics is called emulsion cosmetics, it is the most common type of cosmetics. However, under normal conditions, oil and water are incompatible with each other. After the stirring is stopped, the oil and water return to a layered state, and a stable and uniform dispersion system cannot be achieved. The oily ingredients in creams, lotions and other emulsion products The reason why a uniformly mixed dispersion system can be formed with water is that surfactants are added to it. The special structure of the surfactants enables the incompatible oil and water to be uniformly mixed together to form a Relatively stable dispersion system, that is, emulsion. The effect of Surfactant in emulsion is called emulsification. We call surfactants that play emulsification as Emulsifier. Therefore, there are surfactants in our daily creams and lotions.

(2) Washing and foaming effects

Some surfactants have good washing and foaming effects. The soaps that everyone is very familiar with are very commonly used surfactants. The soaps and soaps we use use soap ingredients (surfactants) to cleanse , Foaming effect, some facial cleansers also play a cleansing effect through the soap ingredients inside, but the soap ingredients have a strong cleaning power, which is easy to cause skin degreasing and is slightly irritating, so dry skin and sensitive skin This kind of cleansing products should not be used. In addition, products such as bath lotions, shampoos, hand sanitizers, and toothpastes are all surfactants that play a cleaning and foaming role.

(3) Solubilization

Surfactants can increase the solubility of some insoluble or hardly soluble substances in water, so that they can be completely dissolved in water, and finally form a transparent state. This effect is called solubilization, and the surface activity that exerts solubilization Agents are also called solubilizers. For example, we want to add an oily ingredient with good emollient properties to the transparent lotion, but the oil cannot be dissolved in the water and can only float on the surface of the lotion in the form of small oil droplets. At this time, we can use the surface The solubilizing effect of the active agent is to dissolve the oily ingredients in the make-up water well by adding the surfactant, and the product finally presents a good transparent appearance. However, it should be noted that the amount of oily components that can be dissolved by solubilization is limited, and it is difficult for a larger amount of oily components to be completely dissolved in water through solubilization. Therefore, with the increase of oily ingredients, the amount of surfactants needs to be increased. The oily ingredients and water are emulsified. This is why some lotions are opaque and milky white, because there are more moisturizing oils on the surface. The active agent emulsifies it with water.

Surfactants can be divided into four categories: anionic, cationic, zwitterionic and nonionic according to their structural characteristics. Among them, anionic surfactants have good washing and foaming effects, and are mostly used in cleaning products; cationic surfactants have good sterilization, antistatic and soft hair effects, and are mostly used in hair conditioners; zwitterionic surface The active agent has a weak cleaning effect, but has good foaming, foam stabilization and thickening effects. It is mostly used as an auxiliary anionic surfactant in cleaning products to enhance the cleaning effect of the product and reduce the irritation; nonionic surfactants are It is good at emulsification and solubilization, and has low irritation. It is mostly used in creams, lotions and water products that need to be solubilized.