Influence of alignment layers on crystal growth of polymer-stabilized blue phase liquid crystals

Chen, Po‐Ju; Chen, Michael; Ni, Shih Ya; Chen, Hung Shan; Lin, Yi-Hsin

doi:10.1364/ome.6.001003

Cited by 22 publications

(14 citation statements)

References 29 publications

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“…These authors also observed that nucleation is mediated by the chemical interactions and anchoring energy between the LC molecules and the surface (29). Phase transitions between BPs have been found to be first order.…”

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confidence: 88%

Mesoscale martensitic transformation in single crystals of topological defects

Martínez‐González

Hernández-Ortíz

et al. 2017

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

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Liquid-crystal blue phases (BPs) are highly ordered at two levels. Molecules exhibit orientational order at nanometer length scales, while chirality leads to ordered arrays of double-twisted cylinders over micrometer scales. Past studies of polycrystalline BPs were challenged by the existence of grain boundaries between randomly oriented crystalline nanodomains. Here, the nucleation of BPs is controlled with precision by relying on chemically nanopatterned surfaces, leading to macroscopic single-crystal BP specimens where the dynamics of mesocrystal formation can be directly observed. Theory and experiments show that transitions between two BPs having a different network structure proceed through local reorganization of the crystalline array, without diffusion of the doubletwisted cylinders. In solid crystals, martensitic transformations between crystal structures involve the concerted motion of a few atoms, without diffusion. The transformation between BPs, where crystal features arise in the submicron regime, is found to be martensitic in nature when one considers the collective behavior of the double-twist cylinders. Single-crystal BPs are shown to offer fertile grounds for the study of directed crystal nucleation and the controlled growth of soft matter.T here is considerable interest in understanding at a fundamental level the processes through which crystals are nucleated, and how they grow and transform between different lattice symmetries. Among crystal-crystal transformations, martensitic transitions are of particular interest, as they involve a collective and diffusionless atomic rearrangement that occurs at velocities comparable to the speed of sound in the material (1). Here, we use liquid crystals (LCs) that exhibit long-range order and crystalline symmetries with lattice constants in the submicron regime, the socalled blue phases (BPs), to study a liquid analog of a crystalcrystal transformation. BPs are thermodynamically stable liquid crystalline states that occur in a narrow range of temperatures between the cholesteric (Chol) and isotropic (I) phases of chiral LCs. In BPs, the molecules are locally oriented and organized in such a way as to form structures known as double-twist cylinders. These cylinders, which arise from a balance of long-range elastic distortions and short-range enthalpic contributions to the free energy, adopt a cubic lattice structure, which is interdispersed by an ordered network of topological defects (disclination lines). Depending on the thermodynamic conditions, the double-twist cylinders adopt a body-centered cubic structure (BCC), which produces the so-called blue phase I (or BPI), or they adopt a simple cubic structure (SC), which corresponds to the so-called blue phase II (or BPII). In both cases, the lattice parameters are on the order of a few hundred nanometers (2-4). BPs exhibit selective light reflections; they have fast electro-optical switching characteristics, with submillisecond response times, and their viscosity is relatively large (3,(5)(6)(7)(8). This c...

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confidence: 88%

Mesoscale martensitic transformation in single crystals of topological defects

Martínez‐González

Hernández-Ortíz

et al. 2017

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

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“…Учитываются условия на границе раздела слоев в сложной конструкции ЖК-ячейки, условия питания и облучения ЖК-мезофазы, способы ориентирования ЖК-молекул, а также модификация мезофазы разного рода частицами, как то: фуллеренами, квантовыми точками, шунгитами, оксидами графена, J-агрегатами, др. [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Вполне понятно, что как процесс сенсибилизации ЖК, так и граничные условия существенно влияют на физические свойства ЖК, в том числе на временны́е параметры устройств на их основе, характеризующие реакцию и релаксацию мезофазы.…”

Section: Introductionunclassified

Temporal Characteristics of Liquid Crystal Cell with WS2 Nanoparticles: Mesophase Sensitization and Relief Features

Каманина¹,

Zubtsova²,

Toikka³

et al. 2020

Liq. Cryst. and their Appl.

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В настоящей работе рассмотрены временны́е параметры (время реакции и релаксации среды) жидкокристаллической ячейки, сенсибилизированной наночастицами WS 2 и сконструированной с учетом модификации проводящего покрытия ITO углеродными нанотрубками. Углеродные нанотрубки осаждались на поверхность проводящего слоя вертикально с применением лазерного метода и ориентационного воздействия электрического поля с напряженностью 600 В/см. Использование двух управляющих функций, а именно процесса сенсибилизации объема мезофазы и наноструктурирование поверхности раздела твердое тело-жидкий кристалл, позволило повысить быстродействие переключения мезофазы и существенно снизить сопротивление проводящих слоев, выполняющих роль ориентанта и проводника. Ключевые слова: жидкие кристаллы, процесс сенсибилизации мезофазы, наночастицы WS 2 , рельеф поверхности границы раздела, углеродные нанотрубки, лазерный ориентированный метод осаждения.

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“…Despite the blue phase was discovered already in 1888, by Austrian botanist Reinitzer [5], its properties were described years later at the end of 20th century. Currently the new technology of observation and analysis allow to get more information about structure of BP domains, their growth [6][7][8], optical properties and potential applications [9][10][11][12][13][14][15][16][17][18]. The temperature range of BP appearance can be extended, by addition of bimesogenic molecules or nanoparticles [19][20][21] and stabilized Email address: martef@if.pw.edu.pl (M. M. Sala- Tefelska) by using a polymer [22].…”

Section: Introductionmentioning

confidence: 99%

Influence of cylindrical geometry and alignment layers on the growth process and selective reflection of blue phase domains

et al. 2018

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In this work the influence of cylindrical shape and alignment layers on light reflection in Blue Phase Liquid Crystal (BPLC) is presented. For the first time, the process of BP domains growth in a capillary is presented. The cylindrical structure, its diameter and alignment layers change the orientations of cubic blue phase (BP) domains and affect their growth. By using temperature and external electric field the uniform structure was obtained. In this study the ability of switching between BP I and chiral phase in a capillary is also shown.

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Influence of alignment layers on crystal growth of polymer-stabilized blue phase liquid crystals

Cited by 22 publications

References 29 publications

Mesoscale martensitic transformation in single crystals of topological defects

Mesoscale martensitic transformation in single crystals of topological defects

Temporal Characteristics of Liquid Crystal Cell with WS2 Nanoparticles: Mesophase Sensitization and Relief Features

Influence of cylindrical geometry and alignment layers on the growth process and selective reflection of blue phase domains

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