Cholesterol-based dimeric liquid crystals: synthesis, mesomorphic behaviour of frustrated phases and DFT study

Liquid crystal dimers and the twist-bend nematic phase. The preparation and characterisation of the α,ω-bis(4-cyanobiphenyl-4′-yl) alkanedioates

“…In particular, liquid crystal dimers proved to be a rich source of new types of intercalated smectic phases (see, for example,references [8][9][10][11][12]) and, rare and unusual phase transition sequences (see, for example, references [13,14]). More recently, interest has focussed on, for example, their flexoelectric behaviour, [15][16][17] T-and H-shaped dimers, [18][19][20][21] non-alkyl spacers, [22][23][24] cholesterylbased dimers, [25][26][27][28][29][30] discotic dimers, [31][32][33] carbohydrate-based dimers, [34] bent core-calamitic nonsymmetric dimers, [35,36] the effects of linking groups, [37] dimers containing new types of mesogenic units and functionalities, [38][39][40][41][42][43][44][45][46] as well as on higher oligomers. [47][48][49][50] Perhaps the most exciting recent discovery involving liquid crystal dimers, however, has been the observation of nematic-nematic transitions for a small number of odd-membered dimers.…”

Phase polymorphism and thermal stability of new cholesterol thioesters derivatives

“…[8] Cholesterol-based dimeric liquid crystals have also been studied in terms of mesomorphic properties of their frustrated phases. [9] Cholesteryl benzoate derivatives, whose transition properties were reported in [10], were also found capable of forming cholesteric liquid crystal glasses. Cholesteric copolysiloxanes with high temperature cholesteric phase are used as a stationary phase in gas chromatography.…”

Effects of chain branching and lateral fluorine substitution on mesomorphism of cholesteryl benzoates

“…[15] The synthesis of various reactive acrylate monomers and their effect on the stability of BP by supporting the formation of a polymer network was carried out by Hussain et al [16] Pinak et al have noted that the polymer backbone formed from reactive monomers stabilises the selfassembled cubic organisation of the BP and plays a key role in achieving faster response times and a reduction in the operating voltage. [17] Recently, cholesterol-based dimeric liquid crystals exhibiting fluidfrustrated BP have also been reported; for example; see reference [18] and references cited therein. The first discovered liquid crystalline cholesteryl benzoate exhibit BPs but those were not recognised as distinct, thermodynamically stable BPs until 1970s.…”