C. Ocak et al., Effects of salts and structure of chiral dopants on the induced pitch frommicellar nematic phases, PHYS CHEM P, 2(24), 2000, pp. 5703-5707
The effect of adding salt to three different micellar chiral nematic phases
, and the effect of structure of two chiral dopants, hexahydromandelic acid
(HHMA) and mandelic acid (MA), on two achiral nematic host phases have bee
n investigated. The addition of salt to the chiral nematic phases increased
the pitch length, and a further addition led to cholesteric-lamellar phase
transition. This phase transition was explained as fusion of individual mi
celles to coherent but defect rich bilayers. The effect of the structure of
HHMA and MA on decylammonium chloride (DACl) and DL-serine hydrochloride d
ecyl ester (DL-SDE) reflected itself in three different phenomena. (i) HHMA
elevates the cholesteric-isotropic phase transition temperature, whereas M
A lowers it, in general. (ii) The HHMA caused a change in diamagnetic aniso
tropy of DACl system, but MA has no such effect. (iii) The beta value of HH
MA in DACl host phase was twice as large as that of MA, but it was only sli
ghtly different from that of MA in DL-SDE system. These phenomena and the c
hirality transfer were interpreted as a result of the shape of the chiral s
olute and solute-solvent interactions.