Chiral doping effect in the B2 phase of a bent-core liquid crystal: The observation of resonant X-ray satellite peaks assigned to the 5/10 layer periodic structure

Takanishi, Yoichi; Ohtsuka, Youko; Takahashi, Yasuhiko; Kang, Sungmin; Iida, Atsuo

doi:10.1209/0295-5075/109/56003

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…Accordingly, this phase can be formed if the effects of chirality or polar order, or a combination of both, are sufficiently large to exceed the elastic energy required for helix formation. Interestingly, a related heliconical SmC* phase with a longer 10 layer helix was induced by doping an achiral polar smectic phase of a bent-core mesogen with a homochiral dopand [130]. This indicates that besides polar order also chirality (Λ) is required for helix formation.…”

Section: Heliconical Smc S P F Hel Phasesmentioning

confidence: 99%

Mirror symmetry breaking in liquids and liquid crystals

Tschierske

2018

Liquid Crystals

101

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In the recent two decades liquid crystal science has contributed significantly to the understanding of mirror symmetry breaking and spontaneous emergence of chirality in fluids. This account tries to summarise the current state of understanding of mirror symmetry breaking in the liquid and liquid crystalline mesophases, ranging from isotropic liquids, via cubic, columnar and tetragonal SmQ phases of polycatenar compounds, the twist bend nematic phases of bent dimesogens to the heliconical and conglomerate type smectic phases of bent-core mesogens. Especially, the importance of dynamic chirality synchronisation of molecular conformers, cooperativity, helical superstructures, layer chirality, network formation, as well as chiral and achiral surface effects is discussed. At the end the transition from local to absolute symmetry breaking, chirality amplification and the relevance for the emergence of uniform chirality in prebiotic fluids and biosystems are considered. Dynamic Mirror Symmetry Breaking Transiently chiral molecules Cooperativity Super structural chirality Chirality synchronisation in fluids Network connectivity

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Section: Heliconical Smc S P F Hel Phasesmentioning

confidence: 99%

Mirror symmetry breaking in liquids and liquid crystals

Tschierske

2018

Liquid Crystals

101

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“…Several recent observations suggest the possibility of chiral superlayer ordering in achiral bent-core mesogens: Takanishi et al have identified such a structure in a SmCP phase of a bent-core mesogen doped with a chi-ral, rod-shaped molecule that as a neat material exhibits SmC * α and ferrielectric phases [20]; Abberley et al have reported a superlayer helix in a smectic phase of bent dimers of molecular rods [21]; Panarin and co-workers have recently proposed, based on AFM evidence, the existence of tilted, helical supermolecular ordering in several achiral bent-core mesogens with 4-cyanoresorcinol bisbenzoate cores [22]. Earlier investigations of this molecular family had concluded, however, that their polar phases were orthogonal, i.e., untilted and therefore not chiral [23,24].…”

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confidence: 99%

Chiral Incommensurate Helical Phase in a Smectic of Achiral Bent-Core Mesogens

et al. 2019

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An achiral, bent-core mesogen forms several tilted smectic liquid crystal phases, including a non-polar, achiral de Vries smectic A which transitions to a chiral, ferroelectric state in applied electric fields above a threshold. At lower temperature, a chiral, ferrielectric phase with a periodic, supermolecular modulation of the tilt azimuth, indicated by a Bragg peak in carbon-edge resonant soft X-ray scattering, is observed. The absence of a corresponding resonant Umklapp peak identifies the superlayer structure as a twist-bend-like helix that is only weakly modulated by the smectic layering.

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“…Furthermore, novel subphases with seven-, eight-and ten-layer periodic structures were reported for Br-containing LCs and Se-containing LC mixtures based on RXS analysis [18,19].…”

Section: Introductionmentioning

confidence: 99%

Resonant x-ray scattering observation of transitional subphases during the electric-field-induced phase transition in a mixture of Se-containing chiral smectic liquid crystals

et al. 2018

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Using resonant x-ray scattering techniques, transitional subphases during the electric-field-induced phase transition of a mixture of Se-containing chiral liquid crystals, 80% AS657 and 20% AS620, in a planar-aligned cell geometry were investigated, where the prototypical phase sequence SmC_{A}^{*}-SmC_{γ}^{*}-AF-SmC^{*} was observed; the transitional subphases were formed during the transition from the three-layer periodicity phase to the ferroelectric phase. In the lower-temperature range where the three-layer SmCγ^{*} phase appeared under the low electric field, nine- and six-layer subphases and a "streak" pattern appeared in sequence after the transition from the SmCγ^{*} phase with increasing applied electric field; the ferroelectric phase was realized. In the higher-temperature range where the four-layer AF phase appeared under a low electric field, the AF phase changed to a three-layer phase at the medium electric field. The twelve-, nine-, and six-layer subphases subsequently appeared in sequence, and finally the ferroelectric phase was generated with increasing electric field. The molecular arrangements of the field-induced subphases, especially the newly found nine-layer periodicity phase, was analyzed. The successive field-induced phase transition of the present results was compared with that of our previous results for pure Se-containing and Br-containing liquid crystals, and the relation to the three-layer ferrielectric phase was discussed.

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Chiral doping effect in the B2 phase of a bent-core liquid crystal: The observation of resonant X-ray satellite peaks assigned to the 5/10 layer periodic structure

Cited by 6 publications

References 21 publications

Mirror symmetry breaking in liquids and liquid crystals

Mirror symmetry breaking in liquids and liquid crystals

Chiral Incommensurate Helical Phase in a Smectic of Achiral Bent-Core Mesogens

Resonant x-ray scattering observation of transitional subphases during the electric-field-induced phase transition in a mixture of Se-containing chiral smectic liquid crystals

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