An amphoteric surfactant refers to a surfactant having both an anionic and a cationic hydrophilic group, and thus the surfactant is cationic in an acidic solution, anionic in an alkaline solution, and similar in a neutral solution. Nonionic properties. Amphoteric surfactant is easily soluble in water, soluble in concentrated acid and alkali solution, and even soluble in concentrated solution of inorganic salt. It has good hard water resistance, little skin irritation, good fabric softness and antistatic property. Good, good bactericidal effect, good compatibility with various surfactants.
These products can be applied in a wide pH range, but the performance under acidic and neutral conditions should be better than that under alkaline conditions in terms of the corresponding ion state under different acid-base conditions. In general, zwitterionic surfactants are more expensive than nonionic surfactants.
The important amphoteric surfactants are dodecyl dimethyl betaine, carboxylate imidazolines and so on. Compared with anionic surfactants, nonionic surfactants are more comprehensive and have fewer defects---only poor detergency and foaming properties. Some properties of amphoteric surfactants are better than nonionic surfactants. The rest of the performance is not behind. Amphoteric surfactants have better foaming ability than general nonionic surfactants - AE has poor foaming ability; better bactericidal ability - relatively nonionic and anionic; better conditioning. Therefore, in liquid detergents, amphoteric surfactants are mainly used in shampoos, followed by skin cleansers such as shower liquids.