How does Washing Detergent Work

Discover the chemistry at work inside your washing machine.

Anionic surfactants are the workhorse ingredients of most washing detergents. They are compounds such as sodium alkyl sulphate and are made up of molecules that have opposite charges at different points {polar molecules).

Water is also made of polar molecules and, when mixed with washing detergent the hydrophilic (water-loving) part of the surfactant molecule attracts to the water molecule, while the hydrophobic (water-hating) part of the molecule adheres to the dirt and grease in your clothes. This makes the dirt and grime more soluble in the water, allowing for easier removal from your clothing.

Another cleaning effect surfactants have is to lower the surface tension of water. Surface tension is created by these polar molecules pulling on one another due to their charge. This accounts for how pond skaters walk on water and why beads of water hang suspended on grass. By lowering the surface tension, the water can become more wet’ and permeate clothes better allowing for a deeper clean.

Interesting Facts about Detergents on Soap History