Open Access. Powered by Scholars. Published by Universities.®
- Publication
Articles 1 - 3 of 3
Full-Text Articles in Physics
Hybrid Rod-Like And Bent-Core Liquid Crystal Dimers Exhibiting Biaxial Smectic A And Nematic Phases, Yan Wang, Hyung Yoon, Hari Bisoyi, Satyendra Kumar, Quan Li
Hybrid Rod-Like And Bent-Core Liquid Crystal Dimers Exhibiting Biaxial Smectic A And Nematic Phases, Yan Wang, Hyung Yoon, Hari Bisoyi, Satyendra Kumar, Quan Li
Satyendra Kumar
Liquid crystal hybrid dimers involving bent-core units and rod-like units were designed, synthesized and investigated by a combination of polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction studies. All the four unsymmetrical dimers 1–4 exhibited stable nematic phases over a wide temperature range. Moreover, dimer 1exhibited the biaxial smectic A (SmA) phase and dimer 2 exhibited a highly ordered mesophase below the nematic (N) phase. Two rod-like and bent-core nematogenic units were covalently linked in dimers 3 and 4 to furnish exclusively the nematic phase. The observation of the biaxial SmA phase underlying the nematic phase in …
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Oleg Lavrentovich
In many colloidal systems, an orientationally ordered nematic (N) phase emerges fromthe isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries …
Stable Amorphous Blue Phase Of Bent-Core Nematic Liquid Crystals Doped With A Chiral Material, Stefanie Taushanoff, Khoa Le, Jarrod Williams, Robert Twieg, B. Sadashiva, Hideo Takezoe, Antal Jakli
Stable Amorphous Blue Phase Of Bent-Core Nematic Liquid Crystals Doped With A Chiral Material, Stefanie Taushanoff, Khoa Le, Jarrod Williams, Robert Twieg, B. Sadashiva, Hideo Takezoe, Antal Jakli
Antal Jakli
We report an induction of the blue phase III (BPIII) at a relatively low and wide ( over 20 degrees C) temperature range in nematogenic achiral bent-core liquid crystals doped with a high twisting power chiral material. The pitch decreases with increasing chiral dopant ratio, and easily reaches the ultraviolet wavelength, so that completely dark texture is obtained under crossed polarizers. Electrooptical switching was achieved in a time range of a few to a few tens of milliseconds. We propose for the stabilization of BPIII that broad-temperature range smectic nano-clusters inhibit the long-range order of the double twisted helical structures, …