Surfactants in Particle Characterization

Surfactants are molecules that decrease surface tension and interfacial tension between a liquid and a solid. They distribute themselves to have a higher concentration at the solid/liquid interface, than in the surrounding liquid phase. This excess concentration arises at the solid/liquid interface because the surfactant's molecular structure consists of one portion that is soluble in a liquid, and another portion which is insoluble in the same liquid.