Liquid Crystals

Pasechnik, S. V.; Chigrinov, Vladimir G.; Shmeliova, Dina V.

doi:10.1002/9783527627660

Cited by 80 publications

(52 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…is close to the dependence η 3 (T). Such situation can take place for a planar surface orientation of a director in the plane normal to the porous axis [3]. Nevertheless, theory predicts the possibility of formation of different orientational configurations in the system under consideration [12,13], which are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…It results in a number of new hydrodynamic effects, like flow induced orientation of LC, dependence of the effective shear viscosity on the flow rate (non Newtonian behavior), arising of specific hydrodynamic instabilities and a backflow under fast turning on (off) of electric fields [3]. The latter effect is of a practical importance as it can be responsible for the essential changes in operating times of liquid crystal devices.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rheological Properties of Liquid Crystals in Porous Polymer Films with Submicron Sizes of Pores

Pasechnik¹,

Shmeliova²,

Torchinskaya³

et al. 2016

Liq. Cryst. and their Appl.

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rheological Properties of Liquid Crystals in Porous Polymer Films with Submicron Sizes of Pores

Pasechnik¹,

Shmeliova²,

Torchinskaya³

et al. 2016

Liq. Cryst. and their Appl.

View full text Add to dashboard Cite

show abstract

“…In mixtures of liquid crystals, the molecules of different components may possess different degrees of nematic ordering. In the mixture, the order parameter expressed by [25,26]: where     (17), (18), (19), and (21) into Eq. (16), we obtain : …”

Section: Order Parametermentioning

confidence: 99%

The Effect of Magnetcic Field on the Phase Transition of Swollen Liquid Crystal Elastomers

Warsono¹,

Nurwantoro²,

Abraha³

2014

Proceedings of the 2014 International Conference on Physics and Its Applications

View full text Add to dashboard Cite

The effect of magnetic fields on the swelling of liquid crystal elastomers (LCE) dissolved in liquid crystal (LC) solvent have been studied. The Flory-Huggins model used to calculate the free energy of an isotropic mixing and the Maier-Saupe model used to calculate the free energy of a nematic mixing. Numerical integration method used to calculate the order parameter and the total free energy of system (consists of : nematic free energy, elastic free energy, isotropic mixing free energy and magnetic free energy) and the calculation results graphed as a function of temperatures for various magnetic fields and as function of magnetic fields for various of temperatures. We find that the magnetic field shifts the transition points towards higher temperatures, increases the energy transition, and induces an isotropic phase to paranematic phase.

show abstract

“…To understand the textures, it is useful to consider a system with the same top and bottom anchoring conditions, but without the perforated Mylar sheet; we can replace the sheet's anchoring conditions with an effective aligning field. In this case, the physics of the Fréedericksz transition, used in the traditional twisted-nematic display, should be recalled (26). In the lower or upper half-cell, the director either "bends to the left" or "bends to the right" from the midplane to the bottom or top boundary.…”

Section: Planar Anchoring and Domain Wallsmentioning

confidence: 99%

Lassoing saddle splay and the geometrical control of topological defects

Tran

Lavrentovich

Beller

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Systems with holes, such as colloidal handlebodies and toroidal droplets, have been studied in the nematic liquid crystal (NLC) 4-cyano-4′-pentylbiphenyl (5CB): Both point and ring topological defects can occur within each hole and around the system while conserving the system's overall topological charge. However, what has not been fully appreciated is the ability to manipulate the hole geometry with homeotropic (perpendicular) anchoring conditions to induce complex, saddle-like deformations. We exploit this by creating an array of holes suspended in an NLC cell with oriented planar (parallel) anchoring at the cell boundaries. We study both 5CB and a binary mixture of bicyclohexane derivatives . Through simulations and experiments, we study how the bulk saddle deformations of each hole interact to create defect structures, including an array of disclination lines, reminiscent of those found in liquid-crystal blue phases. The line locations are tunable via the NLC elastic constants, the cell geometry, and the size and spacing of holes in the array. This research lays the groundwork for the control of complex elastic deformations of varying length scales via geometrical cues in materials that are renowned in the display industry for their stability and easy manipulability.liquid crystals | topological defects | saddle splay | disclinations T he investigation of mechanisms, both chemical and geometrical, to control and manipulate defects in liquid crystals (LCs) is essential for the use of these defects in the hierarchical self-assembly (1-3) of photonic and metamaterials (4, 5), as well as for studies in low-dimensional topology (3, 6-10). For instance, the disclination line networks characteristic of blue phases (11, 12) have been proposed to organize colloidal inclusions (4, 13). But, can similar 3D disclination line networks be designed in the simpler nematic LC? The ubiquitous use of nematic LCs (NLCs) in the display industry is a testament to their efficacy in applications. Wide-ranging studies on the role of nematic elasticity in designing tailored defect structures have focused primarily on the familiar splay, twist, and bend deformations. Recently, however, there has been a renewed interest in exploiting saddle-splay deformations (8,14,15). By confining nematics in cells with properly designed boundary conditions, we demonstrate an array of controlled, defect-riddled minimum energy states that form as a result of saddle-splay distortions, excitable by the system's surfaces. Energy ConsiderationsWe begin with the Frank free energy for a nematic (16, 17):where n ≡ nðxÞ is the (unit) nematic director and K 1 , K 2 , and K 3 are elastic constants that measure the energy cost for splay, twist, and bend deformations, respectively. The final term with the elastic constant K 24 is the saddle splay and, as a total derivative, is absent from the corresponding Euler-Lagrange equation. However, it contributes to the energy when there are defects, potentially stabilizing them by balancing the energy cost of creating a...

show abstract

Liquid Crystals

Cited by 80 publications

References 0 publications

Rheological Properties of Liquid Crystals in Porous Polymer Films with Submicron Sizes of Pores

Rheological Properties of Liquid Crystals in Porous Polymer Films with Submicron Sizes of Pores

The Effect of Magnetcic Field on the Phase Transition of Swollen Liquid Crystal Elastomers

Lassoing saddle splay and the geometrical control of topological defects

Contact Info

Product

Resources

About