The cleaning product is actually a kind of surface-active agent, has a fixed hydrophilic lipophilic group, it is oriented on the surface of the solution, and can make a significant reduction in the surface tension of the material.
The molecular structure of the surface-active agent (
surfactant cleaning agent) is amphiphilic : one end is a hydrophilic group and the other end is a hydrophobic group; hydrophilic group is often polar groups, such as carboxylic acid, amino or amino sulfonic acid, sulfuric acid, and salt, but also the hydroxyl, amide, ether bond and so on; and hydrophobic groups are often nonpolar hydrocarbon chains, such as more than eight carbon atoms' hydrocarbon chain.
Hydrophobic group in the cleaning liquid "grabs" dirt in the cleaning liquid; The hydrophilic group separates the dirt from the cleaning material by emulsification and wetting with the water flow.