X-ray studies of the hexatic phase in liquid crystals with a crystal-B-hexatic-B-smectic-A phase sequence.

Structural studies of the bond-orientational order and hexatic-smectic transition in liquid crystals of various compositions.

We report on the X-ray studies of freely suspended hexatic films of three different liquid crystal compounds. By applying angular X-ray cross-correlation analysis (XCCA) to the measured diffraction patterns the parameters of the bond-orientational (BO) order in the hexatic phase were directly determined. The temperature evolution of the BO order parameters was analyzed on the basis of the multi...

(+) 10E4M6 : a critical A-C* and the first C*-hexatic B liquid crystal phase transitions

2014 We have determined that the C* phase in (+)10E4M6 (4’-(4-methylhexyloxy)phenyl 4-decyloxybenzoate) occurs between two orthogonal phases : an A phase above 70 °C and a hexatic B phase below 31.3 °C. The C*-A transition shows very little temperature hysteresis and seems continuous with a large anomalous heat capacity. X-ray measurements of the tilt angle, 03B8, in the C* phase could be descr...

Bilayered smectic phase polymorphism in the dipolar Gay-Berne liquid crystal model.

We present computer simulations of the Gay-Berne model with a strong terminal dipole. We report the existence of different stable antiferroelectric interdigitated bilayered phases in this model with diverse in-plane organization. The occurrence of these phases depends crucially on the value of the molecular elongation kappa. For kappa=3 we find an interdigitated bilayered smectic-A phase (absen...

Ac-Calorimetry Studies at the Hexatic-B Smectic-A and Crystal-B Hexatic-B Phase-Transitions in 2 Compounds With Hydrogen-Bonding

Novel modulated Hexatic Phases in Symmetric Liquid Crystal Dimers

Homologues of the dimeric a, w-bis(4-n~alkylanilinebenzylidene-4'-oxy)alkanes (m.OnO.m) have been synthesised with spacer lengths n ranging from 9 to 12 methylene units and with terminal alkyl chain lengths m of10, 12 and 14 Characterisation of these materials has been carried out by X-ray diffraction, differential scanning calorimetry and optical microscopy. In six of these compounds a novel m...