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.
Crystals from stars: A new supramolecular synthon, based on tris(triazolyl)triazine (see figure), can interact through hydrogen bonds with benzoic acids and self-organize in columns.
Putting order into ionic liquids: Ionic liquid (IL)-based nonaqueous lyotropic liquid crystals (LLCs) exhibit extraordinarily high extraction capacity, excellent separation selectivity, and easy recycling. The introduction of self-assembled nanostructures into IL systems is an efficient way to enhance the recognition ability for H-bond donor molecules. The IL-based LLCs successfully combine the unique properties of ILs and LCs and provide a new platform for high-performance separation.
B planar, B aligned: A planarized triphenylborane, bearing three 3,4,5-tridodecyloxyphenyl groups, forms a hexagonal columnar liquid-crystalline phase at ambient temperature. It has a columnar π-stacked structure and ambipolar carrier-transport properties with hole- and electron-mobility values of 3×10−5 cm2 V−1 s−1 and approximately 10−3 cm2 V−1 s−1, respectively.
Three in one: A series of toroidal cyclo-2,9-tris-1,10-phenanthroline macrocycles with a unique hexaaza cavity are reported (see figure). Yamamoto aryl–aryl coupling is a versatile tool for the cyclotrimerization of functionalized 1,10-phenathroline precursors. For the first time, the liquid crystallinity and self-assembly on surfaces could be studied for a macrocycle of the torand family.
A new series of selenide and diselenide liquid crystals containing cholesterol were synthesized and characterized. Most of the materials presented good thermal stability with SmC* and SmA* phases over a wide temperature range. The prepared diselenides also have potential biological applications, and they showed good antioxidant properties.
The curious incident of the mesogen in the twist–bend nematic phase: A large number of new materials that exhibit the “twist–bend nematic phase” have been prepared, allowing several trends between structure and liquid-crystalline behaviour to be found.
Smectic porphyrins: The replacement of two meso-aryl groups of porphyrins with phenylethynyl or naphthylethynyl substituents increases the melting points of the resultant porphyrins by about 100 °C and has allowed thermotropic liquid crystallinity to be demonstrated, including a unique switch from columnar to smectic phase.
On the same side: Dinaphthopyrene-diimides derived from 1,8-disubstituted pyrene, with both substituents on the same side, stack into columns to form hexagonal and rectangular liquid crystals and thus fully function as semi-flexible self-assembling disks (see figure). In contrast, their centrosymmetric isomers derived from 1,6-disubstituted pyrene are less prone to form liquid crystals.
Liquefying DNA: A series of solvent-free DNA melts that exhibit both liquid-crystal ordering and melting into isotropic liquids have been generated by electrostatic complexation of DNA with surfactants. Stable smectic mesophases and liquid phases are obtained in the −20 °C to 200 °C temperature range without thermal degradation of the DNA.
Out of the woods: Novel mesoporous and nanostructured materials can be generated by templating approaches based on cellulose-based liquid crystals derived from trees. This Review focuses on materials templated by cellulose nanocrystals, since their chiral nematic order allows their use in various optical applications such as optical filters, sensors, and optoelectronics.
Di- and tricationic organic salts combine the properties of corresponding monocationic salts with individual features due to the presence of different charged heads on the cation structures. This allows their use in different fields of application such as ionic liquid crystals and gel phases.
Riot of color: Alternate stacking of aromatic donor and acceptor building blocks by complementary and directional charge-transfer interactions produce versatile supramolecularly assembled materials including micelles, vesicles, nanotubes, fibrillar gels, folded polymers, cross-linked networks, and liquid-crystalline phases.