A Lyotropic Chiral Smectic C Liquid Crystal with Polar Electrooptic Switching

Chiral Liquid Crystals: Structures, Phases, Effects

“…It should be noted that in accordance with solid state systems and expected from theory, the b-coefficient changes sign from negative for a first order to positive for a second order transition [89]. Recently, an interesting discovery has been made in demonstrating the first lyotropic ferroelectric liquid crystal [90], which consists of a phenylpyrimidine core with a chiral diol head group coupled via a spacer group, in polar solvents like water or formamide. Thermotropic and lyotropic phases exhibit a wealth of similarities.…”

Origin of the Director Tilt in the Lyotropic Smectic C* Analog Phase: Hydration Interactions and Solvent Variations

“…[14] As seen in the phase diagram (Figure 7b)t he surfactant indeed forms as table enantiotropic L* a 0 phase in mixtures with formamide, the stability range of which is, however,s ignificantly reduced in comparison to water,t hat is,t he phase is only stable between1 2a nd 25 wt %o ff ormamide in concentrationa nd over am aximum temperature range of about 20 K. Contraryt o what was stated earlier [1] the L* a 0 phase found in mixtures with formamide is enantiotropic, even though its temperaturea nd concentrationr ange is largely extended on cooling. [14] As seen in the phase diagram (Figure 7b)t he surfactant indeed forms as table enantiotropic L* a 0 phase in mixtures with formamide, the stability range of which is, however,s ignificantly reduced in comparison to water,t hat is,t he phase is only stable between1 2a nd 25 wt %o ff ormamide in concentrationa nd over am aximum temperature range of about 20 K. Contraryt o what was stated earlier [1] the L* a 0 phase found in mixtures with formamide is enantiotropic, even though its temperaturea nd concentrationr ange is largely extended on cooling.…”

“…[1] The presence of the long-range-correlated director tilt has already been proven by two-dimensionalX -ray diffraction experiments [1] and by the existence of clearly separated tilt domains (Figure 3), which occur in surface-stabilized samples in analogyt ot hermotropic SmC and SmC* phases. Polarized micro-Raman spectroscopy reveals that the director tilt in the L* a 0 phase originates from at ilting of the aromatic 2-phenylpyrimidine cores of the surfactant molecules.…”

“…Recently,w ereported the discovery of al yotropic analogo f the thermotropic ferroelectric smecticC*( SmC*) phase, [1] which we suggested to denote as the L* a 0 phase in accordance with thermotropica nd lyotropic nomenclature. [2,3] This new lyotropic phase is formed in mixtures with water or formamide and ac ertains urfactant, in the molecular structureo fw hich ar igid 2-phenylpyrimidinecorei sl inked to the hydrophilic diol headgroupb ya ne thylene glycol spacer ( Figure 1).…”

Liquid crystal research highlights

“…Now Bruckner and colleagues report a rigorous study of the lyotropic counterpart of SmC*, using polarising optical microscopy, X-ray diffraction and electro-optic measurements to firmly establish aspects of its structure and elucidate its properties. [6] A polar electro-optic effect is reported, analogous to its thermotropic counterpart. The phase also exhibits a macroscopic helicoidal structure which, the authors suggest, raises the question of how chiral interactions are communicated across layers when they are, in the lyotropic case, separated by a layer of achiral solvent.…”