Novel cyclodextrin (CD)-based amphiphilic poly­(carboxylic acid)­s that self-assemble into highly ordered smectic liquid crystalline mesophases were investigated as a novel class of protonic conductors. These structurally well-defined materials are synthesized from nontoxic and environment-friendly CDs, which possess a unique face-to-face pseudosymmetry. By taking advantage of such geometry, a series of flexible tetraethylene glycol groups terminated with a carboxylic acid functionality were introduced to the CD’s secondary face, resulting in the formation of long-range 2D hydrogen-bond networks in the smectic mesophases over a wide temperature window. This new material was found to exhibit impressive proton conductivities in solid states, up to 1.4 × 10–2 S cm–1 at 70 °C and 95% humidity. This constitutes the first report of amphiphilic CD-based liquid crystals applied as proton conductive materials.

Inverting the substitution patterns of amphiphilic cyclodextrins has uncovered their unprecedented abilities to form hexagonal columnar mesophases.

A cyano-tetraethylene glycol functionalized amphiphilic cyclodextrin forms liquid crystalline self-assembly that shows promising ion conductivity (Li+).

An ovel familyo fa mphiphilic cyclodextrin(CD)-based liquid crystalst hat bear O-acetylated oligoethyleneg lycol chains at the secondary face is reported. Unlike most of the previously reported liquid crystals (LC) based on chemically modified CDs, which depend on H-bonding as the primary intermolecular forces, the presentC Dd erivatives self-assemble into highly or-dered smecticl iquid crystal phases via the weakerd ipoledipole intermolecular interactions.T he obtained materials are found to display much improved properties such as improved thermostability,r educed clearingt emperatures, and better fluidity.T he present work opens up new possibilities to design CD-based LC materials.

Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5”-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, thiadiazole derivatives formed smectic C and soft crystal lamellar phases, and maintained lamellar order down to room temperature. Variation of the terminal alkyl chains also influenced the observed phase sequence. Single crystal structures revealed the face-to-face orientation of molecules within the layers in the solid-state, a packing motif that is rationalized based on the shape and dipole of the thiadiazole ring, as corroborated by density functional theory (DFT) calculations. The solution opto-electronic properties of the systems were characterized by absorption and emission spectroscopy, cyclic voltammetry, and time-dependent density functional theory (TD-DFT).

The strategic tuning of liquid crystalline phase behaviour by adjusting molecular symmetry was investigated. A family of sixteen symmetrical and unsymmetrical 2,6-di(4'-n-alkoxybenzoyloxy) naphthalene derivatives were prepared and their liquid crystal properties examined by differential scanning calorimetry, polarised optical microscopy, and x-ray diffraction. All mesogens formed nematic phases, with longer-chain analogues also exhibiting smectic C phases at lower temperatures. Melting temperatures of the compounds strongly depend on molecular symmetry, whereas clearing transitions are relatively insensitive to this effect. A detailed analysis indicates that the clearing point can be predicted based on the nature of the terminal alkyl chains, with only a secondary effect from molecular symmetry. Moreover, low symmetry molecules showed a greater tendency to form smectic C phases, which was ascribed to the selective depression of the melting point versus the SmC-N transition. This demonstrates that molecular symmetry-breaking is a valuable tool both for tuning liquid crystalline phase range and for increasing a material's polymorphism.

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