Effect of headgroup chirality in nanoassemblies. Part 1. Self-assembly of D-isoascorbic acid derivatives in water

L-(+)-ascorbic acid and D-(-)-isoascorbic acid are epimers, with an opposite configuration at the C5 stereogenic chiral center. Single chained surfactants that carry a L-ascorbic or D-isoascorbic acid residue as hydrophilic headgroup and an alkanoate tail as hydrophobic chain were synthesized. We refer to these as L-ASCn and D-ASCn, with n=8, 10, or 12. The role of the headgroup configuration in determining the nature of both the pure compounds, and their nano assembly in aqueous dispersions were studied. Surface tension, infrared spectroscopy, differential scanning calorimetry, conductivity, small angle X-ray scattering, and wide angle X-ray diffractometry were used to characterize surfactant properties as a function of temperature and concentration. The L and D headgroups forms have significantly different hydration. This greatly affects the structure and stability of the aggregates in the micellar and in the coagel states.