Evidence of the hexagonal columnar liquid-crystal phase of hard colloidal platelets by high-resolution SAXS.

We report Small-Angle X-ray Scattering (SAXS) measurements of the columnar phase of hard colloidal gibbsite platelets. We have been able to create large oriented domains of the columnar phase both perpendicular and parallel to the sample wall, varying the volume fraction of platelets and adding non-adsorbing polymer to the dispersion. In conjunction with the increased resolution of the SAXS setup, this allowed a detailed analysis of the columnar phase, providing unambiguous evidence for the hexagonal nature of the phase.