Top 10 unbelievable historical concurrencies. An anionic surfactant is a macromolecule, usually in the sulfonate or sulfate group of chemicals such as sodium laureth sulfate, that acts as an active surface agent to lower the surface tension of liquids.op 10 unbelievable historical concurrencies. An anionic surfactant is a macromolecule, usually in the sulfonate or sulfate group of chemicals such as sodium laureth sulfate, that acts as an active surface agent to lower the surface tension of liquids.