The Unusual Mesophases and Properties Exhibited by a Family of Glycosteroids.

In this article we describe research on the synthesis and characterization of a family of "Janus" amphiphiles composed of disaccharide head groups and alkaloid units joined together via a methylene linker, and bearing a lateral aliphatic chain of varying length. The condensed phases formed by self-organization of the products as a function of temperature were characterized by differential scanning calorimetry, thermal polarized light microscopy, and small angle X-ray scattering, allied with computational modelling and simulations. Structural studies on heating specimens from the solid showed that some homologues exhibited lamellar, columnar and bicontinuous mesophases, whereas the same homologues revealed different phase sequences on cooling from the amorphous liquid.

Dyes for guest-host liquid crystal applications: a general approach to the rapid computational assessment of useful molecular designs.

A set of experimental dichroic order parameters ranging from +0.66 to -0.22 was obtained by recording polarized UV-visible absorption spectra from aligned samples of fifteen different guest anthraquinone and azo dyes in the nematic host 4-cyano-4'-pentylbiphenyl (5CB).

Experimental and Computational Study of a Liquid Crystalline Dimesogen Exhibiting Nematic, Twist-Bend Nematic, Intercalated Smectic, and Soft Crystalline Mesophases.

Liquid crystalline dimers and dimesogens have attracted significant attention due to their tendency to exhibit twist-bend modulated nematic (N) phases. While the features that give rise to N phase formation are now somewhat understood, a comparable structure-property relationship governing the formation of layered (smectic) phases from the N phase is absent. In this present work, we find that by selecting mesogenic units with differing polarities and aspect ratios and selecting an appropriately bent central spacer we obtain a material that exhibits both N and intercalated smectic phases.

Efficiency improvements in a dichroic dye-doped liquid crystal Fresnel lens.

A dichroic dye-doped liquid crystal Fresnel lens was fabricated and investigated to observe the combination of phase and amplitude modulation based focusing. An anthraquinone dichroic dye was doped into a liquid crystal host, which when in the Fresnel lens configuration, generates a Fresnel zone plate with alternating "transparent" and "opaque" zones. The zones were induced by using photo-alignment of a light-sensitive alignment layer to generate the alternating pattern.

Shape segregation in molecular organisation: a combined X-ray scattering and molecular dynamics study of smectic liquid crystals.

Temperature-dependent X-ray scattering studies have been carried out on 4-undecyloxy-4'-cyanobiphenyl (11OCB) and 4-(12,12-dimethyltridecyloxy)-4'-cyanobiphenyl (t-Bu-11OCB) in the smectic A phase, from which their layer spacings and translational order parameters were obtained. Marked differences between the layer structures of the two compounds were demonstrated, showing that the addition of the t-Bu group results in a higher translational order parameter and wider layer spacing for t-Bu-11OCB than 11OCB. Fully atomistic MD simulations of both compounds run for >1000 ns demonstrated the spontaneous formation of smectic mesophases from isotropic starting geometries, and experimental trends in order parameters and absolute layer spacings were shown to be replicated well.