Structure of cubic mesomorphic phases determined by low-temperature transmission electron microscopy and small-angle x-ray scattering

Abstract

Cubic phases exist in many amphiphile/water systems at high solute concentrations between the lamellar and hexagonal phases, and at lower amphiphile concentrations between micellar and hexagonal phases. The structure of the latter is still controversial. Structural models that have been suggested to satisfy the experimental data all lacked direct evidence to prove their validity. The structural model we report here is based on a combination of direct and indirect experimental techniques. Direct imaging by low-temperature (cryo) transmission electron microscopy (TEM) of vitrified specimens provides the geometry and size of the «building blocks» of the phase, in this case globular micelles, and shows directly the existence of a cubic phase