The surfactant can reduce the surface tension of water by adsorption on the gas-liquid two-phase interface, and also decrease the interfacial tension of the oil by adsorption in the liquid interface.
Many surfactants can also be assembled into aggregates in the solution of the body. Vesicles and micelles are the classified collection collectively. The concentrations of surfactants starting to form Micelles are called critical micelle concentrations or CMC. When micelles are formed in water, the tail of the micelles forms a nucleus that can wrap the oil droplets, and their (ionic/polar) heads form a shell to keep in touch with the water. The surfactant gathers in the oil, the aggregate refers to the reverse micelles. In the reverse micelles, the head at the core, the tail to maintain full contact with the oil. Surfactants are usually divided into four main categories: anions, cations, non-ionic and amphoteric ions (double electrons). The thermodynamic dynamics of surfactant systems are important, both theoretically and in practice. Because the surfactant system represents a system between ordered and disordered material states.
Surfactant solutions may contain ordered phases (micelles) and disordered phases (free surfactant molecules and/or ions). For example, commonly used detergents can improve water penetration in the soil, but the effect lasts only a few days (many standard detergents contain a certain amount of chemicals, such as sodium and bromine, that can damage plants and are not suitable for soil). Commercial soil wetting agents will continue to be effective for some time and eventually will be degraded by micro-organisms. However, some may have an impact on the biological cycle of aquatic organisms, so care must be had to prevent these products from flowing into the surface runoff and excessive products should not be washed away.