Morphological transitions in dilute solutions of sugar-based zwitterionic dimer betaine surfactants

In the present study the transient morphological evolution of surfactant aggregates of dilute dimer acid betaine solutions was investigated by light scattering techniques and surface tension measurements. It is shown that dimer acid betaine solutions undergo a spontaneous formation of larger thermodynamically stable vesicles within the time period of several days via intermediate aggregation states. The vesicular structures can be destroyed by dilution but will reversibly rebuild with the same time constants indicating a true equilibrium situation similar. In contrast to other vesicle-forming surfactant systems, dimer acid betaines exhibit aggregation mechanism that are similar to those of two-component surfactant mixtures, as it has both dimeric and zwitterionic properties promoting vesicle formation.