MAGNETIC-FIELD-INDUCED ORIENTATIONAL ORDERING OF ALKALINE LYOTROPIC SILICATE - SURFACTANT LIQUID-CRYSTALS

Macroscopically oriented silicate-surfactant liquid crystals are produ ced by slow cooling of lamellar and hexagonal mesophases through their isotropic-anisotropic phase transition in an 11.7 T magnetic field. C omparisons of in situ experimental and simulated H-2 NMR spectra quant ify the degrees of orientational order in the silicate-surfactant Liqu id crystals. The overall orientations of the mesophases with respect t o the applied magnetic field depend upon the combined diamagnetic susc eptibilities of the individual molecular species in the multicomponent surfactant-silicate mixtures. As a result, macroscopic alignment of t hese liquid crystalline systems can be controlled by adjusting their c omposition: lamellar or hexagonal domains are shown to adopt different orientations, according to the diamagnetic susceptibilities of differ ent organic additives present in otherwise identical mixtures. These r esults demonstrate the utility of liquid crystal processing strategies for organizing inorganic-organic hybrid materials over mesoscopic and macroscopic length scales.