Nematic and Smectic Phases with Proper Ferroelectric Order.

A material showing a sequence of three ferroelectric liquid crystalline phases below the paraelectric nematic phase is synthesized and studied. The polar order of molecules appearing due to the dipole-dipole interactions in the ferroelectric nematic, N, phase is preserved also in the smectic phases: orthogonal SmA and tilted SmC. The ferroelectric ground state of both smectic phases is confirmed by their second harmonic generation (SHG) activity and polarization switching.

Polar Order in a Fluid Like Ferroelectric with a Tilted Lamellar Structure - Observation of a Polar Smectic C (SmC) Phase.

The spontaneous polarisation of the SmC phase is over two orders of magnitude larger than that found in conventional ferroelectric SmC phase of chiral materials used in some LCD devices. Fully atomistic molecular dynamics simulations faithfully and spontaneously reproduce the proposed structure and associated bulk properties; comparison of experimental and simulated X-ray scattering patterns shows excellent agreement. The materials disclosed here have significantly smaller dipole moments than typical polar liquid crystals such as RM734 which suggests the role of molecular electrical polarity in generating polar order is perhaps overstated, a view supported by consideration of other molecular systems.

Spontaneous chiral symmetry breaking in polar fluid-heliconical ferroelectric nematic phase.

Spontaneous mirror symmetry breaking by formation of chiral structures from achiral building blocks and emergent polar order are phenomena rarely observed in fluids. Separately, they have both been found in certain nematic liquid crystalline phases; however, they have never been observed simultaneously. Here, we report a heliconical arrangement of achiral molecules in the ferroelectric nematic phase.

Lithium salt of a pro-mesogenic [-CBH] derivative: anisotropic Li ion transport in liquid crystalline electrolytes.

Li ion conduction in two aligned liquid crystalline electrolytes consisting of 10 mol% Li salt of a pro-mesogenic anion derived from [-1-CBH] in non-ionic hosts was investigated. Using electrochemical impedance spectroscopy (EIS), the ionic conductivity in the parallel () and perpendicular () directions of the electrolyte samples was determined using two types of cells: an interdigitated gold electrode and a nylon 6-coated ITO cell. The ratio of ionic conductivities / in the electrolyte with a nona(ethylene oxide) spacer was about 3 in the entire SmA phase, while in the shorter homologue, the ratio monotonically increases from about 0.

Disentangling optical effects in 3D spiral-like, chiral plasmonic assemblies templated by a dark conglomerate liquid crystal.

Chiral thin films showing electronic and plasmonic circular dichroism (CD) are intensively explored for optoelectronic applications. The most studied chiral organic films are the composites exhibiting a helical geometry, which often causes entanglement of circular optical properties with unwanted linear optical effects (linearly polarized absorption or refraction). This entanglement limits tunability and often translates to a complex optical response.