Amphoteric surfactants
Amphoteric surfactants are surfactants with both anionic and cationic hydrophilic groups, so these surfactants are cationic in acidic solution, anionic in alkaline solution, and non-ionic in neutral solution. Amphoteric surfactants are easily soluble in water, soluble in concentrated acid and alkali solutions, even in the concentrated solution of inorganic salts can also be dissolved, good hard water resistance, skin irritation is small, fabric softness is good, good antistatic properties, good bactericidal effect, and a variety of surfactants with good compatibility.
These products can be used in a wide pH range, but from the viewpoint of the ionic state corresponding to different acid and alkaline media conditions, the performance under acidic and neutral conditions should be better than under alkaline conditions. Generally speaking, the price of amphoteric surfactants is higher than that of nonionic surfactants.
Important amphoteric surfactants include dodecyldimethyl betaine and carboxylate imidazolines. Compared with anionic surfactants, nonionic surfactants have more comprehensive performance and fewer defects–only the detergency and foaming are poorer; compared with nonionic surfactants, some of the performance of amphoteric surfactants is better, and the rest of the performance does not lag behind. Amphoteric surfactants have better foaming ability than general nonionic surfactants—the foaming ability of AE is poor; better bactericidal ability—relative to nonionic and anionic. Better conditioning. Therefore, in liquid detergents, amphoteric surfactants are mainly used in shampoo shampoos, followed by skin cleansers such as shower solutions.
Cationic surfactants
Common cationic surfactants include cetyl dimethyl ammonium chloride (1631), octadecyl trimethyl ammonium chloride (1831), cationic guar gum (C-14S), cationic panthenol, cationic silicone oil, dodecyldimethyl amine oxide (OB-2) and so on. Cationic surfactants are different from other surfactants in that they have poor detergency and foaming properties, and often have a certain degree of irritant toxicity (low).
Cationic surfactants are used as auxiliary surfactants in liquid detergents – the conditioning agent component of formulations with very small amounts; they are generally used in higher-grade products, mainly in shampoos. Cationic surfactants are not directly compatible with anionic surfactants. There is a possibility of good results with cationic and anionic surfactants, but there is a higher risk of precipitation (crystallization).
There are many varieties of cationic surfactants used in shampoos, and the frequency of their use is relatively decentralized – not concentrating on the use of one or two varieties, and they are often formulated into conditioning agent products. Cationic surfactants account for a small share of surfactant production and tend to be more expensive than other types of surfactants. Compared with various types of surfactants, cationic surfactants have the most prominent adjusting effect and the strongest bactericidal effect; despite the shortcomings of poor decontamination, poor foaming, poor compatibility, irritation, and expensive, it is not an alternative to other types of surfactants as an adjusting agent component in the high-grade liquid detergents for shampoo shampoo. It is worth noting that cationic surfactants can only be used as conditioning agent components or bactericides.
