Cationic surfactant

It can dissociate in water, has a surface active molecular structure, and partially exhibits hydrophobic cation behavior. Such active agents are referred to as cationic surfactants. As early as 1896, F. Kraft et al. found that the hydrochloride salt of hexadecylamine has soap foaming properties, but it was not until 1928 that cationic surfactants were used industrially, such as fiber softeners. Antistatic agents, water repellents, dyeing auxiliaries, mineral flotation and fungicides. However, its consumption is lower than that of anionic surfactants and nonionic surfactants, and it is generally used mainly for special purposes such as reducing friction and bactericidal action. Cationic surfactants dissociate surface-active cations in water, which have opposite charges to anionic surfactants and are often referred to as "reverse soaps." In terms of its chemical structure, it contains at least one long-chain hydrophobic group and one positively charged hydrophilic group. Long chain hydrophobic groups are typically derived from fatty acids or petrochemicals. The positive charge of surface active cations is generally carried by nitrogen atoms and can also be carried by sulfur and phosphorus atoms, but most of the hundreds of cationic surfactants currently commercially available contain positively charged nitrogen atoms. Therefore, fatty amines are important raw materials for cationic surfactants. Cationic surfactants, like other types of surfactants, adsorb on the interface or surface, forming a micelle in solution at a certain concentration (critical micelle concentration, ie CMC), thereby reducing the surface tension of the solvent and exhibiting Surface activity. It has the functions of emulsification, solubilization, wetting, washing and dispersing. The washing action of cationic surfactants is limited, and its bacteriostatic property and affinity for adsorption to hard surfaces are prominent. Typically, the hard surface is negatively charged and the positively charged cationic surfactant has a very pronounced activity. Cationic surfactants are easily absorbed by human skin, hair and teeth. They can be used as sanitizing agents, antiseptic agents, germiciides, fungicides, antistatic agents, textile softeners (Texil softeners), corrosion inhibitors ( Corrosion inhibitors, antifoaming agents, and flotation agents. In cosmetics, it is mainly used as a bactericide, bacteriostatic agent, hair conditioner, skin softener and anti-caries additive. In the late 1980s, cationic surfactants accounted for about 8% to 10% of total surfactant sales.