Formation of a columnar liquid crystal in a simple one-component system of particles

Self-assembly of a triply periodic continuous mesophase with Fddd symmetry in simple one-component liquids

Triply periodic continuous morphologies (networks) arising as a result of the microphase separation in block copolymer melts have so far never been observed self-assembled in systems of particles with spherically symmetric interaction. We report a molecular dynamics simulation where two simple one-component liquids form upon cooling an equilibrium network with the Fddd space group symmetry. This complexity reduction in the liquid network formation in terms of the particle geometry and the number of components evidences the generic nature of this class of phase transition, suggesting opportunities for producing these structures in a variety of new systems.

Hybrid photoluminescent materials containing a benzobisthiazole core for liquid crystal and gel applications

Tetra- and hexacatenar amide compounds containing a linear centrosymmetric benzobisthiazole core were synthesized with good yields. These compounds were characterized and their structures confirmed by elemental analysis, and FT-IR, Maldi mass and NMR spectroscopy. All compounds exhibited excellent thermal stability up to 330 °C. The tetracatenar series containing a double substitution in the meta positions did not show mesomorphic behaviour, whereas the hexacatenar and tetracatenar series having a double substitution in the meta and para positions showed liquid crystal properties with optical textures typical of columnar mesophases corroborated by POM analysis. The mesomorphic properties were dependent on the length, number and position of alkoxy chains attached at the end of the rigid core. XRD studies of the hexacatenar series showed the hexagonal columnar structure of the mesophases. Photoluminescence properties in solution were observed in the visible region, with good quantum yields. In the solid state, these compounds behave as blue emitters and they are able to change colour with acid or base addition. The hexacatenar benzobisthiazole compound with an alkoxy chain of 14 carbons presented properties of a supergelator in chloroform, leading to the formation of a fluorescent organogel material with fluorescence emission in the blue region.