Ionic liquid crystals.

Data on the synthesis, structures and properties of ionic, coordination, organometallic and organoelement compounds with liquid-crystal properties are surveyed. The substances examined are new in the chemistry of the liquid-crystal compounds. Their potential applications are described. The bibliography includes 211 references.

http://iopscience.iop.org/article/10.1070/RC1993v062n04ABEH000019/pdf

Metal-containing liquid-crystal phases

Structures of the thermotropic mesophases of lead(II) decanoate are reassigned following optical and X-ray diffraction studies. These results, and those of D.S.C., Raman and 207Pb N.M.R. spectroscopy, indicate formation of a lower temperature mesophase involving mainly increased lateral disorder, and a higher temperature Lα (smectic A) phase resulting from chain disordering and decreased lead-carboxylate interaction. Comparison of experimental thermodynamic data for the phase transitions with theoretical data in the literature indicates that the entropy change for the lower to higher mesophase transition is dominated by the increase in chain disorder.

Mesophase formation in lead(II) decanoate

Conductivity (σ) measurements are performed on micellar systems consisting of tetradecyltrymethylammonium bromide (TTAB) in the presence of n-butanol (BuOH). It is found that σ vs BuOH molarity dependence at fixed TTAB concentration shows an unusual sinusoidal behavior. Other parameters of the systems are studied and an approximation to the conductivity of the system is made. The unusual dependence of conductivity on alcohol concentration at fixed surfactant concentration is discussed and some evidence of the competition of the viscosity of water−alcohol solution and the degree of ionization on conductivity of the systems are presented, rather than a phase transition as it was proposed earlier.

Some Physicochemical Properties of TTAB−Butanol Micellar Aqueous Solutions

An isotropic, clear phase at high alcohol content is found in a system composed of calcium dodecyl sulfate, water, and an alcohol of medium chain length, like pentanol, hexanol, heptanol, or octanol This phase is located in that region of the phase diagram in which L3 phases are classically formed Most ionic surfactants, however, only form sponge phases when the ionic charge of the surfactant molecules is sufficiently shielded by excess salt At 5% surfactant and octanol as cosurfactant, the L3 phase disappears if more than 5% of the calcium ions are substituted by sodium Calcium dodecyl sulfate, in some aspects, behaves like a nonionic or double-chain surfactant The phase discussed in this article is completely transparent, has low viscosity, and exhibits neither birefringence nor yield stress Viscosity, electrical conductivity, and freeze-fracture electron microscopy indicate the sponge structure of the phase In contrast to typical L3 phases, small-angle neutron-scattering experiments show a peak 

Investigation of the L3 Phase in Systems Containing Calcium Dodecyl Sulfate, Alcohol, and Water

Interpretation des resultats en terme de mouvement anisotropique des ions Na + et RCOO − dans la mesophase et de mouvement libre dans la phase isotrope

J. E. Bonekamp

Papers

Thermotropic ionic liquid crystals. 3. Sodium-23 nuclear magnetic resonance study of the ionic mesophase of sodium n-alkyl carboxylates