Lyotropic Smectic B Phase Formed in Suspensions of Charged Colloidal Platelets

Here, we present the first observation of a smectic B (Sm-B) phase in a system of charged colloidal gibbsite platelets suspended in dimethyl sulfoxide (DMSO). The use of DMSO, a polar aprotic solvent, leads to a long range of the electrostatic Coulomb repulsion between platelets. We believe this to be responsible for the formation of the layered liquid crystalline phase consisting of hexagonally ordered particles, that is, the SmB phase. We support our finding by high-resolution X-ray scattering experiments, which additionally indicate a high degree of ordering in the SmB phase.