The Basic Properties Of Surfactants

Jan. 06, 2022

Surfactants reduce the surface tension of water by adsorbing at the gas-liquid interface, and can also reduce the oil-water interfacial tension by adsorbing at the liquid interface. Many surfactants can also aggregate into aggregates in the bulk solution.

Both vesicles and micelles are such aggregates. The concentration at which the surfactant begins to form micelles is called the critical micelle concentration or CMC. When micelles are formed in water, the tails of the micelles form a core that can envelop the oil droplets, and their (ionic/polar) heads can form a shell that remains in contact with water. Surfactants aggregate in the oil, and aggregates are referred to as reverse micelles. In reverse micelles, the head is in the core and the tail is kept in full contact with the oil. Surfactants are generally divided into four categories: anionic, cationic, nonionic and zwitterionic (two electrons). The thermodynamics of the surfactant system is very important, both in theory and in practice. Because the surfactant system represents a system between the state of order and disorder. The surfactant solution may contain an ordered phase (micelle) and a disordered phase (free surfactant molecules and/or ions).

For example, commonly used detergents can improve water penetration in the soil, but the effect only lasts a few days (many standard laundry detergents contain a certain amount of chemicals, such as sodium and bromine, which are not suitable for soil because they can damage plants). Commercial soil wetting agents will continue to work for a period of time, and will eventually be degraded by microorganisms. However, there are some that will affect the biological cycle of aquatic organisms, so care must be taken to prevent these products from flowing into the surface runoff. Excess products should not be decontaminated.