Micellar properties and growth of cationic fluorocarbon surfactant; diethanolheptadecafluoro-2-undecanolmethylammonium chloride

The micellar properties of a cationic fluorocarbon surfactant, diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMAC), are studied by surface tension, fluorescence of pyrene-3-carboxaldehyde (PCA), and electric conductivity measurements. These measurements indicate that DEFUMAC solution provides a low surface tension and that its micelles present higher polar conditions under PCA than do cationic hydrocarbon surtactant micelles. Moreover, the micellar elongation induced by increasing concentrations of salt and surfactant concentration is observed by use of dynamic light scattering, transient electric birefringence, and viscosity measurements. The elongation by addition of salt can be explained by a multiple equilibrium description, while the elongation by increasing surfactant concentration is rapid above a particular concentration, viz. second CMC. Consequently, DEFUMAC micelle elongates more rapidly than do corresponding cationic hydrocarbon surfactants with chloride counterion.