There are two opinions today. Some say that amphoteric surfactants are harmful substances that should not be used. Others argue that this is not so dangerous at all, and their use is necessary. To understand why this dispute arose, it is necessary to understand what these components are.
general description
It is worth starting with the fact that the addition of amphoteric surfactants to shampoo, for example, is simply necessary. The thing is that if you wash your hair only with water, you can remove only those contaminants that can be dissolved in water. Dust, dirt and sweat do not dissolve in a liquid, but on the contrary, they will create strong compounds with skin lipids. Because of this, the use of chemicals is necessary to remove such substances from the skin and hair.
Today, there are 4 types of surfactants that differ in the polarity of their molecules. On this basis distinguish anionic, cationic, nonionic or amphoteric. It is worth noting that some call the amphoteric group still ionic. Because of this, there are problems, since people believe that there are 5 such groups - amphoteric surfactants, ionic and others. However, this is not so and there are only 4 of them.
Description of the first category
This type includes anionic and cryptanionic sulfo compounds. In addition, these substances belong to tensides, which are most strongly incompatible with dirt among others. And it is precisely this chemical substance that is most complained by all those who oppose the use of surfactants. However, if you look at things from a practical point of view, then this group is the best additive in any detergent. Anions and cryptanions most effectively remove dirt from contacted surfaces. For this reason, today almost all effective detergents contain such an additive.
Receiving and application
It should be noted right away that it was precisely this group of people that they learned to receive first of all. Over time and the development of mankind, it was possible to obtain anionic tensides from proteins and fats, alkalized with ash and other compounds of this type. Today, the main source of raw materials for producing anionic and cryptanionic surfactants is coconut, palm, rapeseed oil, as well as butter from cow or goat milk.
As for the principle of operation of this category of surfactants, it is based on the special structure of the molecules of this group. The thing is that they consist of two parts - hydrophilic and hydrophobic. One of them (hydrophilic) loves water, the other, on the contrary. The first part of the molecule allows the substance to come into contact with water and wash off with it. The second part, on the contrary, comes in contact with non-polar substances, that is, dust, dirt, fats and other things. During shampoo washing, for example, hydrophobic parts trap dirt and other similar substances in a micelle - a hollow ball. It turns out that during washing off the shampoo with water, all impurities are also removed.
Of the main advantages of this group stands out quick, high-quality and complete removal of dirt from the surface of the skin, as well as appendages. In addition, the molecules are capable of foaming, have bactericidal and bacteriostatic properties.
Amphoteric and nonionic groups
All manufacturers of quality products that contain anionic surfactants understand that it is necessary to soften their effect as much as possible in relation to human lipid mantle, but at the same time not to reduce their cleansing effect. It is to solve this problem that amphoteric surfactants are used. Some also refer to the nonionic and amphoteric groups as co-surfactants.
This group of tensides is intended to neutralize the acid reaction of anions. In addition, they also contribute to the speedy breakdown of these substances, and also condense and reduce airiness, that is, the diameter of the foam bubbles.
It is necessary to say that the types of amphoteric surfactants are the most expensive representatives among all products. To obtain this substance, it is necessary to carry out the procedures of squeezing, extraction, infusion, rectification and oxidation of natural substances. To obtain the substance, both plant and animal raw materials are suitable. There are several well-known and common products that are used to extract these additives. Amphoteric surfactants are obtained from soap dishes, algae, pulp of apples, root crops, palm oil and dairy products.
The principle of the amphoteric group
To understand the importance of adding amphoteric surfactants, you need to have at least the slightest understanding of chemical processes. It is known that oppositely charged substances will be attracted in pairs to each other, because of which their relationship will decrease, and they themselves will precipitate. All this will lead to the fact that the cleansing effect is greatly reduced. It was possible to solve this problem by introducing precisely amphoteric surfactants.
Their principle of operation is based on the fact that they are able to easily give or attach an electronic pair of the medium in which they are located. In other words, in an acidic environment, they are able to change their properties. If they are placed in an alkaline medium, they will act as anions, and in the acidic medium they will play the role of cations.
Substance properties
In cosmetics, amphoteric surfactants are necessary in order to protect the skin and hair from dryness, as well as irritation. In addition, the tensides of this group are able to restore the stratum corneum of the epidermis, hair keratin, soften, and also increase the elasticity of connective tissue.
Nonionic compounds
As mentioned earlier, there are no more than 4 types of basic surfactants. Nonionic surfactants and amphoteric surfactants are two different categories, but amphoteric surfactants are also ionic, which is approximately the same thing. Those substances are considered ionic, after dissolution of which these same ions remain. In other words, nonionic surfactants are the only group among others, after dissolution of which no ions are formed. Fatty alcohol esters such as polyglycolic and polyglycolic are included in this category. Such a group can include, for example, feistenside - a fluid with good fluidity, which consists of citric acid and fatty alcohols.
In order to obtain such additives, it is necessary to carry out the procedure of hydroxyethylation of vegetable oils. Castor oil, wheat, flax, sesame, calendula, parsley sprouts became the main raw materials for obtaining the non-ionic group. One of the key features of this group is that they can exist either in liquid or in pasty form. That is, such detergents cannot be contained in solid detergents (soap, powder).
As for the use of this group of surfactants, esters are a substance such as dispersion micellar solution. Very often, it is also called smart soap. The essence of the name is revealed by the fact that the detergent is able to remove dirt and grease from the surface of the skin or hair without damaging the protective mantle of the skin.
If we talk about the properties of the non-ionic category of substances, they can increase the safety, environmental friendliness and softness of the composition. The biodegradability of this group of tensides is 100%. They are able to activate therapeutic additives that may be contained in a detergent for hair, can restore damaged layers of the epidermis, have a bradykinase and polishing effect.
Are amphoteric additives harmful?
Naturally, many are interested in the question of what harm amphoteric surfactants do to human skin and its health in general. Here it’s worth mentioning right away that if you look at the reverse side of the effects of all surfactants, then the amphoteric group is the safest among them.
Description of human exposure to amphoteric category
It is worth starting with the fact that the foam that is formed under the influence of these particular surfactants is the most moderate, and it can also improve the quality of the hair. In addition, amphoteric additives themselves cause minimal irritation to the scalp, but at the same time they can remove the irritation caused by other substances, and can be more severe. If amphoteric and anionic tensides are combined, then foam formation can be improved, and the harm to the skin can be reduced. If you connect this group with cations, then you can significantly improve conditioning products, which will positively affect the health of the skin and hair.
If we talk about detergents, then amphoteric products are also quite common in them, but in the form of betaine additives. To get just such components for the detergent, you have to use fatty acids of coconut, soybean, sunflower oil. In addition, the opinion that amphoteric surfactants will be harmful to humans can be changed by adding it to shampoo for children. This is due precisely to the fact that the substance is quite harmless, and when it enters the cornea, it does not cause irritation.
Harm other groups
Some believe that the anionic group is quite dangerous for humans. And the danger is precisely what they are added to the composition for, that is, they too carefully remove the fats, while degreasing the skin. This leads to the destruction of the hydrolipidic film, damage to skin lipids and the penetration of surfactants into deeper layers. The microflora balance may be disturbed, and the mechanisms responsible for physiological fat formation may also be impaired. We can say that the skin dries too much under the influence of anions, which is why it ages faster.
It is also noted that the accumulation of this group of surfactants is possible in the heart, brain, liver, and especially in fat deposits. Once in these places, anionic surfactants continue to destroy the body from the inside and this process lasts long enough. He is also able to interfere with the metabolic functions of the body.
All this leads to the fact that there is a need to neutralize such consequences. It is for this reason that the amphoteric group of surfactants is abundantly applied, despite the fact that they are the most expensive.
Summary
If to summarize all of the above, then we can draw one conclusion. Natural resources are used to produce any surfactant. However, if you do not follow the rules of mixing or consistency, or if you do not add, for example, amphoteric tensides, then detergents can cause harm.