Characterization of new gemini surfactant micelles with phosphate headgroups by SANS and fluorescence spectroscopy

Two series of bisphosphate surfactants having different hydrophobic tails and variable number of spacer methylene groups have been synthesized. Detailed small-angle neutron scattering studies were carried out with their aqueous solutions to study their micellar properties. For some of these new surfactants, critical micellar concentrations and micropolarities were also determined. It has been found that the micelles were ellipsoidal for surfactants with short spacers having C12H25 hydrophobic tails. However, the corresponding surfactants having C16H33 chains and similar m-values afforded micelles that were disk-like and rod-like.