Ordering of the 7CB liquid crystal induced by nanoscale confinement and boundary lubrication

Zhang, Xiangjun; Liu, Xiaoxiang; Zhang, Xiaohao; Tian, Yu; Meng, Yonggang

doi:10.1080/02678292.2012.715686

Cited by 18 publications

(14 citation statements)

References 26 publications

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“…However, given the edge-on surface anchoring they do not result from logpile structures, but from hexagonal arranged circular concentric bent columnar structures as illustrated Figs. 3c and 7a-d(i) [30,47,49]. See also movie M4, where virtual and real scattering patterns are shown in direct comparison as a function of ω rotation for d=86 nm.…”

Section: X-ray Diffraction and Translational Ordermentioning

confidence: 99%

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Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

et al. 2019

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light the whole structure is described as a metamaterial [1][2][3]. A monolithic membrane traversed by a parallel array of cylindrical nanochannels represents such a metamaterial, see illustration in Fig. 1. The advent of tailorable porosity at the nanoscale and thus of an adjustable "meta-atomic" structure offers new opportunities to tailor the optical anisotropy of such metamaterials. Effective optical properties, not achievable by base materials, are possible [2-8], specifically adjustable birefringence. This is of particular relevance for important polarisation management components, such as waveplates and compensators, that play an essential part in modern optical communication systems [9].A versatile route to fine-tune optics of porous materials is filling the pore space with a liquid crystal (LC) [10,11]. In the bulk case LCs play a dominant role for the manipulation of optical anisotropy [12]. By embedding LCs in nanoporous media the self-assembly and self-healing mechanisms can be used to design a new soft-hard metamaterial. The LC adds optical functionality, whereas the arXiv:1911.10052v1 [cond-mat.soft]

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Section: X-ray Diffraction and Translational Ordermentioning

confidence: 99%

“…An axial arrangement, see Fig. 3(d), which is of interest with respect to electronic applications, could only be achieved in DLCs with increased core-rigidity compared to HAT6 [49] or by non-circular channel cross-sections [30].…”

Section: Introductionmentioning

confidence: 99%

Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

et al. 2019

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“…Spatial confinement of liquid crystals can alter their physico-chemical properties substantially. Novel phase behaviour, complete suppression of phase transitions and inhomogeneous structures and dynamics have been reported experimentally and validated both by analytical theory and computer simulation [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In particular the advent of porous media with tailorable pore shapes and tuneable pore size from the macro-, via the meso-to the microscale have resulted in an increased number of studies aimed at an understanding of liquid crystalline behaviour in these interface-dominated geometries [1,11,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Adsorption from Binary Liquid Solutions into Mesoporous Silica: A Capacitance Isotherm on 5CB Nematogen/Methanol Mixtures

Kityk,

Gor,

Huber

2021

Preprint

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We present a capacitance method to measure the adsorption of rod-like nematogens (4-cyano-4'-pentylbiphenyl, 5CB) from a binary liquid 5CB/methanol solution into a monolithic mesoporous silica membrane traversed by tubular pores with radii of 5.4 nm at room temperature. The resulting adsorption isotherm is reminiscent of classical type II isotherms of gas adsorption in mesoporous media. Its analysis by a model for adsorption from binary solutions, as inspired by the Brunauer-Emmett-Teller (BET) approach for gas adsorption on solid surfaces, indicates that the first adsorbed monolayer consists of flat-lying (homogeneously anchored) 5CB molecules at the pore walls. An underestimation of the adsorbed 5CB amount by the adsorption model compared to the measured isotherm for high 5CB concentrations hints towards a capillary filling transition in the mesopores similar to capillary condensation, i.e. film-growth at the pore walls is replaced by filling of the pore centers by the liquid crystal. The experimental method and thermodynamic analysis presented here can easily be adapted to other binary liquid solutions and thus allows a controlled filling of mesoporous materials with non-volatile molecular systems.

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“…1 To investigate their effectiveness for use in tribology, their applications as lubricants have been examined. 2 Liquid crystals have been examined to apply as base fluids [3][4][5][6][7][8][9][10][11] and as additives. [12][13][14][15][16][17][18][19] However, lubrication by liquid crystals with dissolved additives (eg, fatty acids) has received little attention.…”

Section: Introductionmentioning

confidence: 99%

Synergy of two fatty acids as additives on lubricity of a nematic liquid crystal 5CB

Tadokoro

Araya

Watanabe

et al. 2018

Lubrication Science

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In examining the lubricity of a nematic liquid crystal (4‐pentyl‐4′‐cyanobiphenyl [5CB]), synergy of 2 fatty acids (stearic acid [C18] and behenic acid [C22]) as additives was observed. In “friction measurements” using a ball‐on‐plate‐type tribometer, the friction coefficient for the “mixed‐additive” lubricant (5CB‐C18‐C22) was lower than those for the “single‐additive” lubricants (5CB‐C18 and 5CB‐C22). This synergy mechanism was discussed with considering the results obtained in other tests: “orientation observations” in a stationary cell using polarising microscopy and “surface topography measurements” of adsorbed films using atomic force microscopy. As a result, it is believed that the microscopic patterned surface formed by the mixed additive strengthens the surface anchoring of 5CB, which leads to increase in the effective viscosity of 5CB and therefore to decrease in the macroscopic friction coefficient in the mixed lubrication regime.

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Ordering of the 7CB liquid crystal induced by nanoscale confinement and boundary lubrication

Cited by 18 publications

References 26 publications

Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials

Adsorption from Binary Liquid Solutions into Mesoporous Silica: A Capacitance Isotherm on 5CB Nematogen/Methanol Mixtures

Synergy of two fatty acids as additives on lubricity of a nematic liquid crystal 5CB

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