Anchoring Energy of Some Nematic Liquid Crystals at Aligment Layers of Different Topography

Frunzǎ, S.; Roques, Y.; Farenc, J.; Stoenescu, D; Traverse, J.P.

doi:10.1002/crat.2170310819

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…The lower polar anchoring energy leads to the sharper change of director orientation in the central area of the cell when the value of the magnetic field increases [30] and, consequently, the intensity of light increases faster. The values of polar anchoring energy are in the range 10 -2 -10 -1 erg/cm 2 and these values are in good agreement with data presented in [31]. The values of polar anchoring energy for 5CB doped with ionic surfactant are less than for undoped LC.…”

Section: Resultssupporting

confidence: 89%

Polar anchoring energy and tilt angle measured by magneto-optical technique in nematic doped with ionic surfactant

et al. 2020

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The surface anchoring of nematic doped with ionic surfactant is considered in comparison with an undoped one. Tilt angle of director at the substrates coated with a polymer orienting film was determined by the null method in rotating magnetic field. Frederiks transition in the magnetic field was chosen as a convenient technique for measuring the polar anchoring energy W. The temperature dependences of the anchoring energy for various nematic cells have been obtained. The W values for nematic doped with ionic surfactant are less than for the undoped one. The factors affecting the accuracy of the measurements are discussed. The accuracy is higher for thinner LC layers and for weak anchoring energy.

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Section: Resultssupporting

confidence: 89%

Polar anchoring energy and tilt angle measured by magneto-optical technique in nematic doped with ionic surfactant

et al. 2020

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“…The preferred director alignment on the nematic-substrate interface has previously been determined to be planar in experiments involving an interface between glass coated with a layer of PVA and 5CB, with a well-characterised anchoring strength in the range | CNS | = 10 −4 -10 −3 Nm −1 [45,[68][69][70]. The preferred director alignment on the gas-nematic interface has previously been determined to be homeotropic [60]; this was confirmed using a separate experiment on a free-standing film of 5CB.…”

Section: Experimental Investigation Of a Ridge Of 5cbmentioning

confidence: 99%

Weak-anchoring effects in a thin pinned ridge of nematic liquid crystal

et al. 2023

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A theoretical investigation of weak-anchoring effects in a thin two-dimensional pinned static ridge of nematic liquid crystal resting on a flat solid substrate in an atmosphere of passive gas is performed. Specifically, we solve a reduced version of the general system of governing equations recently derived by Cousins et al. [Proc. Roy. Soc. A, 478(2259):20210849, 2022] valid for a symmetric thin ridge under the one-constant approximation of the Frank-Oseen bulk elastic energy with pinned contact lines to determine the shape of the ridge and the behaviour of the director within it. Numerical investigations covering a wide range of parameter values indicate that the energetically-preferred solutions can be classified in terms of the Jenkins-Barratt-Barbero-Barberi critical thickness into five qualitatively different types of solution. In particular, the theoretical results suggest that anchoring breaking occurs close to the contact lines. The theoretical predictions are supported by the results of physical experiments for a ridge of the nematic 4'-pentyl-4-biphenylcarbonitrile (5CB). In particular, these experiments show that the homeotropic anchoring at the gas-nematic interface is broken close to the contact lines by the stronger rubbed planar anchoring at the nematic-substrate interface. A comparison between the experimental values of and the theoretical predictions for the effective refractive index of the ridge gives a first estimate of the anchoring strength of an interface between air and 5CB to be (9.80 ± 1.12) × 10 −6 Nm −1 at a temperature of (22 ± 1.5) • C.

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