Liquid-crystalline phases were discovered more than a century ago.1 Up to now, tens of thousands of organic liquid crystals were discovered. In contrast, only a few mineral liquid crystals were characterized. In comparison to organic liquid crystals, inorganic ones may possess enhanced electrical, optical, magnetic properties and thermal stability. 1 The currently known lyotropic mineral liquid crystals, which formed in dispersions of anisometric inorganic particles at some critical concentration, were summarized in two review articles. 2,3 The liquid-crystalline phase of V2O5 suspensions shows an electro-optic effect and is used for measurement of residual dipolar couplings of unlabeled biomolecules. 4,5 Mineral liquid-crystal moieties can differ largely in size from one system to another, but they are in a colloidal range.

The lamellar phase in colloidal suspensions of positively charged platelets of layered double hydroxides (LDHs) was studied with synchrotron small angle X-ray scattering and optical observations.

The cloud points (CP) of aqueous solutions of two ethylene oxide–propylene oxide–ethylene oxide tri-block copolymers (EO)10(PO)16(EO)10 and (EO)1(PO)17(EO)1 were measured in the presence of additives, such as salts, alkalis, acids, polymer and ionic surfactant. The results obtained in this study indicated that salts decrease the CP of the two tri-block copolymers in the order of NaCl>CaCl2>MgCl2 and Na3PO4>Na2SO4>NaCl. Alkalis caused a sharp drop of CP of the two tri-block copolymers. Acids increased the CP. Water soluble polymer such as polyvinylpyrrolidone (PVP), hydrolysis polyacrylamide (HPAM) and cation-polyacryamide (cation-PAM) decreased the CP. Ionic surfactants such as sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) increased the CP. The extent of lowering depends on the structure and concentration of additives and the number of ethylene oxide group of tri-block copolymers.