Electric-field-induced disclination migration in a Grandjean-Cano wedge

Strömer, J. F.; Marenduzzo, Davide; Brown, C. V.; Yeomans, J. M.; Raynes, E. P.

doi:10.1063/1.2181691

Cited by 8 publications

(4 citation statements)

References 16 publications

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“…ref. 26 where the velocity of the disclination in a cholesteric device was shown to scale in a way consistent with this argument). In addition, backow † ( Fig.…”

Section: Juho Lintuvuori Is a Postdoctoral Research Associate In The supporting

confidence: 63%

Switching hydrodynamics in liquid crystal devices: a simulation perspective

et al. 2014

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In liquid crystal devices it is important to understand the physics underlying their switching between different states, which is usually achieved by applying or removing an electric field. Flow is known to be a key determinant of the timescales and pathways of the switching kinetics. Incorporating hydrodynamic effects into theories for liquid crystal devices is therefore important; however this is also highly non-trivial, and typically requires the use of accurate numerical methods. Here, we review some recent advances in our theoretical understanding of the dynamics of switching in liquid crystal devices, mainly gained through computer simulations. These results, as we shall show, uncover interesting new physics, and may be important for future applications.

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“…ref. 26 where the velocity of the disclination in a cholesteric device was shown to scale in a way consistent with this argument). In addition, backow † ( Fig.…”

Section: Juho Lintuvuori Is a Postdoctoral Research Associate In The supporting

confidence: 63%

Switching hydrodynamics in liquid crystal devices: a simulation perspective

et al. 2014

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“…cholesteric rheology [59,60,61,62,63,64] and the effect of flow on device switching [65,66,67,68,69,70,71,72,73]. Because of their disclination structure the kinetics and the rheology of the blue phases is an exciting, but demanding, numerical problem which requires intensive numerical resources.…”

Section: Hydrodynamic Equationsmentioning

confidence: 99%

Numerical results for the blue phases

Alexander

Yeomans

2009

Liquid Crystals

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We review recent numerical work investigating the equilibrium phase diagram, and the dynamics, of the cholesteric blue phases. In equilibrium numerical results confirm the predictions of the classic analytical theories, and extend them to incorporate different values of the elastic constants, or the effects of an applied electric field. There is a striking increase in the stability of blue phase I in systems where the cholesteric undergoes helical sense inversion, and the anomalous electrostriction observed in this phase is reproduced. Solving the equations of motion allows us to present results for the phase transition kinetics of blue phase I under dielectric or flexoelectric coupling to an applied electric field. We also present simulations of the blue phases in a flow field, showing how the disclination network acts to oppose the flow. The results are based on the Landau-de Gennes exapnsion of the liquid crystal free energy: that such a simple and elegant theory can predict such complex and subtle physical behaviour is remarkable.

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“…4(a): it increases linearly with the thickness in the untwisted region and drops suddenly as it approaches the 1𝜋 twisted region. The maximum retardance of the untwisted region is 𝛤 max = 405 nm, which is close to the retardance of wedge cell of ℎ = 𝑃(𝑇)/4, which is Δ𝑛(𝑇) * 𝑃(𝑇)/4 = (0.170*9.15 μm)/4 = 389 nm, indicating that the position of the edge dislocation that separates untwisted to πthe twisted region is located at ℎ = 𝑃(𝑇)/4 in the N * phase [27]. The retardance measurement and director profile in the small portion of untwisted and 2π twisted regions of the N F * phase at 55 °C are shown in the bottom inset of Fig.…”

Section: Resultsmentioning

confidence: 62%

Chiral ferroelectric nematic in Grandjean-Cano wedge cell

Thapa,

Iadlovska,

Basnet

et al. 2023

Liquid Crystals XXVII

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We explore the structures and confinement-induced edge dislocations in Grandjean-Cano wedge cells filled with the recently discovered chiral ferroelectric nematic (NF ∗ ) and chiral antiferroelectric smectic-Z (SmZA ∗ ). The chiral mixture is formed by DIO mesogen doped with a chiral additive. Wedge cells with parallel and antiparallel rubbing at the opposite plates show quantitatively different structures which is attributed to the polar in-plane anchoring of the spontaneous polarization at the rubbed substrates. The helical pitch shows a non-monotonous temperature dependence upon cooling, increasing as the temperature is lowered to the N ∗ -SmZA ∗ phase transition. The SmZA ∗ formed from an untwisted N ∗ in the thin portion of the wedge shows a bookshelf (BK) geometry, whereas the twisted N ∗ transforms into a twisted planar (PA) SmZA ∗ structure. In the NF ∗ phase, the untwisted N ∗ becomes twisted in a wedge with antiparallel assembly of plates and monodomain in wedges with parallel assembly. The twisted regions of NF ∗ show only one type of Grandjean zones separated by thick edge dislocations with Burgers vector 𝑏 = 𝑃; the neighboring regions differ by 2π- twist.

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Electric-field-induced disclination migration in a Grandjean-Cano wedge

Cited by 8 publications

References 16 publications

Switching hydrodynamics in liquid crystal devices: a simulation perspective

Switching hydrodynamics in liquid crystal devices: a simulation perspective

Numerical results for the blue phases

Chiral ferroelectric nematic in Grandjean-Cano wedge cell

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