Characterization of the dipeptide based micellar systems undecanoic alanine-alanine and undecanoic alanine-glycine

Surfactant are surface-active-agents, meaning surfactants have the ability to lower surface tension. In this research, two dipeptide surfactants undecanoic alanine-alanine and undecanoic alanine-glycine were studied to better understand their micellar systems. Variations of pH, temperature, surfactant concentration, and counterion type were examined to determine what effect, if any, changing these variables would have on micelle formation and chiral recognition. The counter ions examined in this study were di-amine alkanes with a different number of methyl groups separating the amines. These counter ions are pH dependent and preliminary results have shown that pH effects the interaction of these counter ions with the amino acid polar head, and in turn effects the physical properties of the surfactants and their micellar behavior. Some of the properties examined include: the critical micelle concentration, Krafft temperature, enantiomeric separation of chiral compounds, hydrodynamic radius of the micelles as well as fraction bound of the surfactant and counterions to the micelles. These systems were studied using proton Nuclear Magnetic Resonance (NMR), Diffusion Order Spectroscopy (DOSY), Capillary Electrophoresis (CE) and a LabQuest 2 with attached conductivity and temperature probes. The results here provide a better insight on the behavior of these dipeptide micellar systems which will aid in future research.