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The twist-bend nematic phase, $N_{\rm TB}$, may be viewed as a heliconical molecular arrangement in which the director $\bf n$ precesses uniformly about an extra director field, $\bf t$. It corresponds to a nematic ground state exhibiting…

The recently discovered twist-bend nematic phase, $\rm N_{tb}$, is a non-uniform equilibrium nematic phase that presents a spontaneous bend with a precession of the nematic director, $\textbf{n}$, on a conical helix with a tilt angle…

The ground state of twist-bend nematic liquid crystals is a heliconical molecular arrangement in which the nematic director precesses uniformly about an axis, making a fixed angle with it. Both precession senses are allowed in the ground…

Soft Condensed Matter · Physics 2014-04-15 Epifanio G. Virga

The nematic twist-bend (TB) phase, exhibited by certain achiral thermotropic liquid crystalline (LC) dimers, features a nanometer-scale, heliconical rotation of the average molecular long axis (director) with equally probable left- and…

In twist-bend nematic (N\textsubscript{TB}) liquid crystals (LCs), the mean molecular orientation exhibits heliconical structure with nanoscale periodicity. On the mesoscopic scale, N\textsubscript{TB} resembles layered systems (like…

Soft Condensed Matter · Physics 2020-11-25 M. Praveen Kumar , P. Kula , Surajit Dhara

We propose an extension of Frank-Oseen's elastic energy for bulk nematic liquid crystals which is based on the hypothesis that the fundamental deformations allowed in nematic liquid crystals are splay, twist and bend. The extended elastic…

Soft Condensed Matter · Physics 2018-04-30 G. Barbero , I. Lelidis

Periodic structures of phases with orientational order of molecules, but homogenous electron density distribution: a short pitch cholesteric, blue phase and twist-bend nematic phase, were probed by a resonant soft x-ray scattering (RSoXS)…

Soft Condensed Matter · Physics 2017-04-19 Mirosław Salamończyk , Nataša Vaupotič , Damian Pociecha , Cheng Wang , Chenhui Zhu , Ewa Gorecka

The understanding of self-organization in the twist-bend nematic $(N_\text{TB})$ phase, identified in 2011 in liquid crystal dimers, is at the forefront of soft matter research worldwide. This new nematic phase develops structural chirality…

Soft Condensed Matter · Physics 2020-10-27 Lech Longa , Wojciech Tomczyk

Dielectric spectroscopy of a twist bend nematic phase of an achiral bent core liquid crystalline compound under DC bias is used to investigate its response to electric field. Two collective relaxation processes are revealed, these are…

Soft Condensed Matter · Physics 2018-09-12 K. Merkel , A. Kocot , J. K. Vij , G. Shanker

We report a dynamic light scattering study of the fluctuation modes in a thermotropic liquid crystalline mixture of monomer and dimer compounds that exhibits the twist-bend nematic ($\mathrm{N_{TB}}$) phase. The results reveal a spectrum of…

The nanostructure of two novel sulfur containing dimer materials has been investigated experimentally by hard and by resonant tender X-ray scattering techniques. On cooling the dimers through the nematic to twist-bend nematic (N-NTB) phase…

Soft Condensed Matter · Physics 2020-11-20 Rony Saha , Chenrun Feng , Chris Welch , Georg H. Mehl , Jun Feng , Chenhui Zhu , James Gleeson , Samuel Sprunt , Antal Jakli

The nonlinear elastic properties of nematic liquid crystals have acquired new interest with the recent experimental observation of bulk modulated nematic phases which are composed by achiral molecules. We extend the Oseen-Zocher-Frank's…

Soft Condensed Matter · Physics 2018-11-09 I. Lelidis , G. Barbero

We review the physics underlying Meyer's conjecture of how macroscopic-scale twist and bend conspire within the Frank-Oseen elasticity theory of nematics to create a heliconical arrangement of the uniaxial, apolar nematic director, the…

Soft Condensed Matter · Physics 2020-09-25 Edward T. Samulski , Alexandros G. Vanakaras , Demetri J. Photinos

It is shown that curved and flat helical double twisted liquid crystal (DTLC) in blue phase, can be unstable (stable) depending of the sign, negative (positive) of sectional curvature, depending on the pitch of the helix of the nematic…

Soft Condensed Matter · Physics 2007-08-27 Garcia de Andrade

Freeze Fracture Transmission Electron Microscopy (FFTEM) study of the nanoscale structure of the so-called "twist-bend" nematic (NX) phase of the cyanobiphenyl (CB) dimer molecule CB(CH2)7CB reveals a stripe texture of fluid layers…

Binary mixtures of the twist-bend nematic-forming liquid crystal CB7CB with the prototypical rod-like liquid crystal 5CB exhibit a twist-bend nematic phase with properties similar to those reported for neat CB7CB. The mixtures appear…

Helical structures are exciting and are utilized in numerous applications ranging from biotechnology to displays to medicine. Accurate description and understanding of resonance effects in helical structures provides crucial knowledge on…

Soft Condensed Matter · Physics 2020-02-04 Yu Cao , Jun Feng , Asritha Nallapaneni , Yuki Arakawa , Keqing Zhao , Georg H. Mehl , Feng Liu , Chenhui Zhu

The twist-bend nematic (Ntb) phase is a recent addition to the nematic (N) phases of liquid crystals (LCs). A net polar order in the Ntb phase under an external electric field was predicted in several recent theoretical studies but yet to…

Soft Condensed Matter · Physics 2022-09-13 Sourav Patranabish , Aloka Sinha , Madhu B. Kanakala , Channabasaveshwar V. Yelamaggad

Stiff, elongated biomolecules such as filamentous viruses, DNA or cellulose nanocrystals are known to form liquid crystals often exhibiting a helical supramolecular organization. Little is known about the microscopic origin, size and…

Soft Condensed Matter · Physics 2016-08-06 Štěpán Růžička , Henricus H. Wensink

The ground state of chromonic liquid crystals, as revealed by a number of recent experiments, is quite different from that of ordinary nematic liquid crystals: it is twisted instead of uniform. The common explanation provided for this state…

Soft Condensed Matter · Physics 2022-03-24 Silvia Paparini , Epifanio G. Virga
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