Cubic phases of ternary amphiphile-water systems.

The reversed cubic phases (Q(II)) are a class of self-assembled amphiphile-water structures that are rich in diversity and structural complexity. These nanostructured liquid crystalline materials are generating much interest owing to their unique surface morphology, biological relevance and potential technological and medical applications. The structure of Q(II) phases in binary amphiphile-water systems is affected by the molecular structure of surfactant, water content, temperature and pressure. The presence of additives also plays an important role. The structure and phase behaviour of ternary Q(II) phases, which are comprised of two miscible amphiphiles and water, significantly differ from the binary system alone. The modulation of the phase behaviour through the addition of a second amphiphile offers an opportunity to control the size and shape of the nanostructures using a 'bottom-up' approach. In this mini-review, we discuss the structure of reversed cubic phases of amphiphile-water systems and highlight the modulation of cubic-phase structure in ternary-phase systems. We also extend this review to bulk cubic phases and the corresponding nanoscale dispersions, cubic-phase nanoparticles.