Supramolecular Structures Based on New Bolaamphiphile Molecules Investigated by Small Angle and Wide Angle X-ray Scattering and Polarized Optical Microscopy

In this paper, we present a study of the structural and self-assembling properties of a new family of bolaamphiphiles. These bolaamphiphiles are unsymmetrical, having one sugar polar head at one side and one glycine betaine polar head at the other side. The variations that we introduced concern the length of the main bridging chain that connects the two polar heads as well as the length of the side chain linked at the anomeric position of the sugar moiety. Another variation concerns the introduction of a diacetylenic unit into the main chain in order to rigidify it. We have performed small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) on the dry compounds as a function of temperature and observed the lamellar structures. We also measured the SAXS and WAXS spectra of aqueous solutions of these compounds that have shown various lamellar structures. The hydrocarbon chain fluidity and, as a consequence, the interlamellar distance varied as a function of temperature. The obtained SAXS and WAXS results are compared with the polarized optical microscopy measurements.