96 research outputs found
Re-entrant ferroelectricity in liquid crystals
The ferroelectric (Sm C) -- antiferroelectric (Sm C) -- reentrant
ferroelectric (re Sm C) phase temperature sequence was observed for system
with competing synclinic - anticlinic interactions. The basic properties of
this system are as follows (1) the Sm C phase is metastable in temperature
range of the Sm C stability (2) the double inversions of the helix
handedness at Sm C -- Sm C and Sm C% -- re-Sm C phase
transitions were found (3) the threshold electric field that is necessary to
induce synclinic ordering in the Sm C phase decreases near both Sm
C -- Sm C and Sm C -- re-Sm C phase boundaries, and it has
maximum in the middle of the Sm C stability region. All these properties
are properly described by simple Landau model that accounts for nearest
neighboring layer steric interactions and quadrupolar ordering only.Comment: 10 pages, 5 figures, submitted to PR
Using lateral substitution to control conformational preference and phase behaviour of benzanilide-based liquid crystal dimers
Open access via the Wiley Agreement Funder: National Science Centre. Grant Number: 2021/43/B/ST5/00240 Acknowledgments D.P. gratefully acknowledges financial support from the National Science Centre (Poland) under the grant no. 2021/43/B/ST5/00240.Peer reviewedPublisher PD
Controlling spontaneous chirality in achiral materials : liquid crystal oligomers and the heliconical twist-bend nematic phase
Peer reviewedPublisher PD
Molecular curvature, specific intermolecular interactions and the twist-bend nematic phase : the synthesis and characterisation of the 1-(4-cyanobiphenyl-4-yl)-6-(4-alkylanilinebenzylidene-4-oxy)hexanes (CB6O.m)
EG and DP acknowledge the support of the National Science Centre (Poland): (Grant Number 2016/22/A/ST5/00319). RW gratefully acknowledges The Carnegie Trust for the Universities of Scotland for funding the award of a PhD scholarship.Peer reviewedPostprin
Flexoelectricity and piezoelectricity - reason for rich variety of phases in antiferroelectric liquid crystals
The free energy of antiferroelectric liquid crystal which takes into account
polar order explicitly is presented. Steric, van der Waals, piezoelectric and
flexoelectric interactions to the nearest layers and dipolar electrostatic
interactions to the nearest and to the next nearest layers induce indirect tilt
interactions with chiral and achiral properties, which extend to the third and
to the fourth nearest layers. Chiral indirect interactions between tilts can be
large and induce helicoidal modulations even in systems with negligible chiral
van der Waals interactions. If indirect chiral interactions compete with chiral
van der Waals interactions, the helix unwinding is possible. Although strength
of microscopic interactions change monotonically with decreasing temperature,
effective interlayer interactions change nonmonotonically and give rise to
nonmonotouous change of modulation period through various phases. Increased
enatiomeric excess i.e. increased chirality changes the phase sequence.Comment: 4 pages, 1 figur
Critical behavior of the optical birefringence at the nematic to twist bend nematic phase transition
This research was supported by the National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. NV acknowledges the support of the Slovenian Research Agency (ARRS), through the research programme P1-0055.Peer reviewedPublisher PD
Helical phases assembled from achiral molecules : Twist-bend nematic and helical filamentary B4 phases formed by mesogenic dimers
Funding Information: National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. Special acknowledgement and thanks to professor Dong Ki Yoon's group for providing the AAO membranes.Peer reviewedPublisher PD
Multi-level chirality in liquid crystals formed by achiral molecules
M.S., D.P., and N.V. acknowledge the support of the National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. E.G. acknowledges the funding from the Foundation for Polish Science through the Sabbatical Fellowships Program. N.V. acknowledges the support of the Slovenian Research Agency (ARRS), through the research core funding no. P1-0055. R.W. gratefully acknowledges the Carnegie Trust for the Universities of Scotland for funding the award of a PhD scholarship. The beamline 11.0.1.2 at the Advanced Light Source at the Lawrence Berkeley National Laboratory is supported by the director of the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.Peer reviewedPublisher PD
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