In the family of surfactants, cationic surfactants are a group with significant antimicrobial capabilities. Representative substances include benzalkonium chloride (Jieermie) and benzalkonium bromide (Xinjieermie). Quaternary ammonium compounds.

The antimicrobial mechanism primarily stems from its unique charge properties. Most bacteria, fungi, and viruses typically carry a negative charge on their cell membrane surfaces. When cationic surfactants come into contact with these microorganisms, the positively charged quaternary ammonium ions in their hydrophilic head groups strongly adsorb and electrostatically bind to the negatively charged cell membranes. This process disrupts the original lipid bilayer structure and functional integrity of the cell membrane, leading to increased membrane permeability and leakage of intracellular contents (such as proteins, nucleic acids, potassium ions, etc.). Simultaneously, cationic surfactants can penetrate into the microbial cells, binding to negatively charged proteins and nucleic acids, causing them to denature and precipitate. This ultimately inhibits microbial metabolism and reproduction, leading to the death of the microorganisms.

Application Scenarios:

Disinfectants and Bactericides:It is widely used for surface disinfection in environments such as hospitals, restaurants, and households, as well as for immersion disinfection of surgical instruments (attention must be paid to concentration and exposure time). Due to its broad-spectrum antimicrobial activity and rapid action, it has become an important chemical disinfectant.

Personal Care Products:In certain specialized facial cleansers, hand soaps, and anti-dandruff shampoos, low concentrations of cationic surfactants are added to kill and inhibit harmful bacteria on the skin's surface, achieving antibacterial effects and treating dandruff (which is associated with Malassezia fungi).

Industrial Corrosion Protection:In industrial fields such as cooling water towers, papermaking, and textiles, it is used as a bactericidal preservative to prevent system decay and blockages caused by microbial growth.

It is important to note that while cationic surfactants have strong bactericidal properties, they are typically more irritating and can form precipitates and lose effectiveness when coexisting with anionic surfactants. Therefore, when using them, it is essential to follow the product instructions, avoid mixing them with regular soap (anionic type), and be mindful of their potential skin irritation.