Liquid crytals (LCs) are probably the most exciting state of matter. They attract scientists across disciplines such as chemistry, physics, materials science, and engineering—theorists and experimentalists alike. These days, you can buy quite affordable LCD TV sets around the corner, but that's just one of the many things liquid crystals can do. The selection of recent research articles presented below illustrates the broad interest in this area of soft condensed matter.
J. W. Goodby, P. J. Collings, T. Kato, C. Tschierske, H. Gleeson,
Handbook of Liquid Crystals
2nd edition, Wiley-VCH, Weinheim, 2014.
Find all articles on liquid crystals in Wiley Online Library...
See the International Liquid Crystal Society's website.
Communicating hydrogen bonds: The director tilt in the novel lyotropic liquid crystalline phase is investigated. Even though the bilayers containing tilted surfactant molecules are separated from each other by layers of more or less disordered solvent molecules, the tilt direction is long-range-correlated. It is shown that the hydrogen bond networks inside the solvent layers play a crucial role in this tilt correlation mechanism (see picture).
Johanna R. Bruckner, Friederike Knecht, Frank Giesselmann
ChemPhysChem, November 24, 2015, DOI: 10.1002/cphc.201500673. Read article
A bent-core mesogen consisting of a 4-cyanoresorcinol unit as the central core and laterally fluorinated azobenzene wings forms four different smectic LC phase structures in the sequence SmA - SmCs -SmCsPAR - M, all involving polar SmCsPS domains with growing coherence length of tilt and polar order on decreasing temperature. The SmA phase is a cluster type de Vries phase with randomized tilt and polar direction; in the paraelectric SmCs phase the tilt becomes uniform though polar order is still short range. Increasing polar correlation leads to a new tilted and randomized polar smectic phase with antipolar correlation between the domains (SmCsPAR) which then transforms into a viscous polar mesophase M.As another interesting feature, spontaneous symmetry breaking by formation of a conglomerate of chiral domains is observed in the non-polar paraelectric SmCs phase.
Mohamed Alaasar, Marko Prehm, Gabriela Tamba, Nerea Sebastian, Alexey Eremin, Carsten Tschierske
ChemPhysChem, November 19, 2015, DOI: 10.1002/cphc.201500891. Read article
We examined self-organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1-butyl-3-methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, into the amphiphile provided homogeneous mixtures showing lyotropic liquid-crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, successive change of mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining LC properties with varying temperature and component ratio, we constructed lyotropic LC phase diagrams. It is of interest that the appearance of these phase diagrams is greatly different according to the selection of [AA]. Comparing them, we found that self-organization behavior of amphiphile in ionic liquids can be tuned by controlling their hydrogen-bond, van der Waals, and π-π interaction ability.
Kanae Fujimura, Takahiro Ichikawa, Masafumi Yoshio, Takashi Kato, Hiroyuki Ohno
Chem. Asian J., November 17, 2015, DOI: 10.1002/asia.201501055. Read article
Ionic associates: Ionic self-assembly of the platinum(II) chelate of 5-sulfo-8-quinolinol functionalized at the periphery with sulfonate groups with ammonium-bearing long-carbon-chain amphiphiles resulted in the formation of air-stable, red-phosphorescent ionic associates that can form crystalline or liquid-crystalline high-quality thin films (see figure).
Franck Camerel, Antoine Vacher, Olivier Jeannin, Joaquín Barberá, Marc Fourmigué
Chem. Eur. J., November 10, 2015, DOI: 10.1002/chem.201502780. Read article.
Luminescent liquid crystals have received significant research interest due to their wide range of applications. Here, new pyridine derivatives were designed as liquid crystalline materials. They were successfully synthesized via appropriate synthetic routes, their structures confirmed by various spectral techniques, and finally characterized for their mesogenic, optical and optoelectronic properties.
Ahipa T. N.
ChemistryOpen, July 14, 2015, DOI: 10.1002/open.201500158. Read article