303173-72-0Relevant academic research and scientific papers
Ferroelectric liquid crystalline polyoxetanes bearing chiral dimesogenic pendants
Lee, Jun-Woo,Dong, Keun Oh,Yelamaggad,Nagamani, S. Anitha,Jin, Jung-Il
, p. 2225 - 2230 (2002)
Two new polyoxetanes bearing dimesogenic pendants were prepared and their liquid crystalline properties were studied by differential scanning calorimetry (DSC), polarizing microscopy, and X-ray diffractometry. The dimesogens consist of cholesterol and bip
Synthesis and characterization of novel chiral dimers exhibiting highly frustrated liquid crystal phases
Hiremath, Uma S.
, p. 4745 - 4753 (2014/06/24)
Two novel series of optically active dimers comprising cholesterol and biphenyl-4-yl 4-(n-alkoxy)benzoate cores interlinked though either an odd-parity/even-parity spacer have been prepared and characterized. They stabilize an extremely complex, frustrated liquid crystalline state viz., the twist grain boundary (TGB) phase with chiral smectic C structure, denoted as TGBC- phase, over a wide (50-110 °C) temperature range. Notably, the dimers with an odd-parity spacer show an additional frustrated liquid crystal phase namely, the blue phase (BP). The presence of such frustrated phases suggests that the synthesized dimers are characterized by high enantiomeric excess and strong molecular chirality. Thus, 12 new optically active, nonsymmetric dimers reported herein constitute new examples of rarely found strongly chiral, optically pure dimers showing frustrated liquid crystal phase over an adequately wide thermal range.
Monodispersive unsymmetrical tetramers exhibiting a columnar phase
Yelamaggad,Anitha Nagamani,Hiremath, Uma S.,Shankar Rao,Krishna Prasad
, p. 207/[507]-229/[529] (2007/10/03)
Oligomeric liquid crystals that are formed by joining two or more mesogenic segments axially through a flexible spacer (or multiple spacers) seem to be interesting materials from the points of view of both basic research and practical applications owing to their multifunctional characteristics and properties similar to those of polymers while retaining fluidity, viscosity etc. associated with those of low molar mass liquid crystals. The synthesis and evaluation of mesomorphic behavior of two novel monodispersive unsymmetrical tetramesogens have been presented here in detail. The molecular design, of these tetramesogens incorporates the cholesteryl ester (as a chiral entity), biphenyl (as a supportive entity for mesomorphism), azobenzene (as a photoactive mesogen), and tolan (as a half-disc) segments interconnected through even-even-odd and odd-even-odd alkylene spacers. The target liquid crystalline tetramers have been realized by employing convenient synthetic strategies, which involves the preparation of two important unsymmetrical dimers and finally their condensation. The molecular structures of all the intermediates and unsymmetrical tetramers have been characterized by spectroscopic analyses. The mesomorphic property of both the unsymmetrical tetramers has been evaluated by optical microscopic, calorimetric and X-ray diffraction studies. Our study reveals that both oligomers show an identical mesophase. While X-ray studies suggest that the structure of the mesophase is similar to that of a rectangular columnar (Colr) mesophase; a pseudoisotropic texture was seen under the microscope.
