Chiral unsymmetrical bent-shaped dimers exhibiting cholesteric phases: synthesis, characterisation and liquid crystalline properties
Year: 2025
Type: article
Abstract: Cholesteric and smectic mesophases in six new unsymmetrical bent-shaped dimers were reported. The homologous series contain a bent-core mesogen and cholesterol mesogenic unit connected through a flexible pentamethylene spacer. The thermodynamic behaviour and liquid crystalline textures were investigated by the combination of differential scanning calorimetry (DSC) and polarising optical microscopy (POM). All derivatives present cholesteric (N*) and smectic (Sm) phases on wide thermal range except the compound with one fluorine atom as substituent that exhibits only chiral nematic phase. For homologues with shorter terminal alkyl chains (hexyl, heptyl) the N* mesophase was narrower than to smectic mesophase, while for the derivative with one fluorine atom into structure only it was observed on wide thermal range. The temperature dependence of the helical pitch of the N* structure was studied, in correlation with the length of the alkyl chain and the presence of one lateral fluorine substituent. The results of the theoretical investigation of cholesteryl derivatives were also reported.
Source: Liquid Crystals
Institution: Université du littoral côte d'opale
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4409410001