1395237-70-3Relevant academic research and scientific papers
Bent-core compounds with two branched chains: Evidence of a new dark conglomerate mesophase
Ocak, Hale,Bilgin-Eran, Belkiz,Prehm, Marko,Tschierske, Carsten
, p. 4590 - 4597 (2013)
Biphenyl-3,4′-diol derived bent-core compounds with branched side chains have been synthesized and characterized to study the influence of terminal branched groups on mesophase properties and transition temperatures of bent-core mesogens. The liquid crystalline properties of the compounds were investigated by differential scanning calorimetry, optical polarizing microscopy and X-ray scattering. Depending on the length of the chain, the size of molecular branches and the position of branched chains, either enantiotropic or monotropic rectangular columnar phases were observed. For one of the compounds combining two different branched side chains, a new type of optically isotropic dark conglomerate phase (MIso[*]) was found. It is proposed to be a distorted version of a non-tilted or only slightly tilted B6-like intercalated smectic phase with additional in plane order.
Effects of molecular chirality on superstructural chirality in liquid crystalline dark conglomerate phases
Ocak, Hale,Bilgin-Eran, Belkiz,Prehm, Marko,Tschierske, Carsten
body text, p. 7773 - 7783 (2012/09/22)
The first examples of polyphilic bent-core compounds consisting of a biphenyl central core, a chiral terminal chain and an oligo(dimethylsiloxane) end group at the other terminus have been synthesized and characterized. The mesomorphic behaviour of the compounds was investigated by differential scanning calorimetry, optical polarizing microscopy, X-ray diffraction and electro-optic methods. The olefinic precursors show monotropic or enantiotropic B1 type mesophases. The siloxane substituted analogues containing a racemic chain exhibit dark conglomerate phases (DC[*] phases) which are composed of chiral domains with opposite chirality, whereas the siloxane derivatives with a homogeneously chiral moiety show "dark enantiomer" phases (DE* phases) with uniform chirality. Under electric fields, different types of ferroelectric switching (FE) smectic and modulated smectic phases were induced. The effects of chain branching, spacer length and molecular chirality on the stability of the DCFE [*] and DEFE* phases and on the field-induced smectic and modulated smectic phases were investigated. The Royal Society of Chemistry 2012.
