88.5 Surfactants and their properties and Applications 8.5.1 Surfactants The surface tension declines steeply Definition: The substances that even at c<×10-3 mol dm3 drastically lower the surface tension of water even at low concentrations. 1)Structure of surfactants The Amphiphilicity is the basic characters of surfactants: They have both polar and nonpolar moieties Hydrophilic group, hydrophobic/lipophilic groupDefinition: The substances that drastically lower the surface tension of water even at low concentrations. 8.5.1 Surfactants The Amphiphilicity is the basic characters of surfactants: They have both polar and nonpolar moieties: Hydrophilic group, hydrophobic/lipophilic group. The surface tension declines steeply even at c < 10-3 mol dm-3 . 1) Structure of surfactants c  §8.5 Surfactants and their properties and Applications