Pub Date : 2024-06-03DOI: 10.1080/21680396.2024.2360391
M.A. Osipov
Possible molecular origin of ferroelectricity in the nematic phase is discussed in detail considering a number of models based on direct dipole–dipole interaction and electrostatic interaction betw...
{"title":"On the origin of the ferroelectric ordering in nematic liquid crystals and the electrostatic properties of ferroelectric nematic materials","authors":"M.A. Osipov","doi":"10.1080/21680396.2024.2360391","DOIUrl":"https://doi.org/10.1080/21680396.2024.2360391","url":null,"abstract":"Possible molecular origin of ferroelectricity in the nematic phase is discussed in detail considering a number of models based on direct dipole–dipole interaction and electrostatic interaction betw...","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-13DOI: 10.1080/21680396.2024.2314305
Oleg D. Lavrentovich
Elastic constants of splay K11, twist K22, and bend K33 of nematic liquid crystals are often assumed to be equal to each other in order to simplify the theoretical description of complex director f...
{"title":"Splay-bend elastic inequalities shape tactoids, toroids, umbilics, and conic section walls in paraelectric, twist-bend, and ferroelectric nematics","authors":"Oleg D. Lavrentovich","doi":"10.1080/21680396.2024.2314305","DOIUrl":"https://doi.org/10.1080/21680396.2024.2314305","url":null,"abstract":"Elastic constants of splay K11, twist K22, and bend K33 of nematic liquid crystals are often assumed to be equal to each other in order to simplify the theoretical description of complex director f...","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140127634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-04DOI: 10.1080/21680396.2022.2115417
T. Sluckin
{"title":"Les vertus des défauts: The scientific works of the late Mr Maurice Kleman analysed, discussed and placed in historical context, with particular stress on dislocation, disclination and other manner of local material disbehaviour","authors":"T. Sluckin","doi":"10.1080/21680396.2022.2115417","DOIUrl":"https://doi.org/10.1080/21680396.2022.2115417","url":null,"abstract":"","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46874063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-10DOI: 10.1080/21680396.2022.2077256
J. Fukuda
Chiral liquid crystals exhibit various intriguing ordered structures arising from helical distortions of the orientational order allowed by chirality. We present our numerical studies on such exotic structures of chiral liquid crystals, particularly focusing on those in a thin film whose thickness is on the order of or smaller than the characteristic helical pitch of the liquid crystal. We first review the Landau–de Gennes continuum theory we use in our calculations, in which the orientational order is described by a second-rank tensor and the free energy of a liquid crystal is given as a functional of . We show that a thin film of a chiral liquid crystal can exhibit a diverse variety of ordered structures involving topological line defects (disclination lines), depending on film thickness, temperature, and type of surface anchoring (normal, planar, and planar degenerate). Such exotic structures include a hexagonal lattice of Skyrmions, a whirl-like localized structure that finds in its place in a wide variety of condensed matter systems. A thin film of a chiral liquid crystal thus provides an interesting platform for the investigation of exotic structures of orientational order arising from the frustration between the bulk ordering and the spatial confinement with surface anchoring.
{"title":"Exotic structures of a thin film of chiral liquid crystals: A numerical study based on the Landau-de Gennes theory","authors":"J. Fukuda","doi":"10.1080/21680396.2022.2077256","DOIUrl":"https://doi.org/10.1080/21680396.2022.2077256","url":null,"abstract":"Chiral liquid crystals exhibit various intriguing ordered structures arising from helical distortions of the orientational order allowed by chirality. We present our numerical studies on such exotic structures of chiral liquid crystals, particularly focusing on those in a thin film whose thickness is on the order of or smaller than the characteristic helical pitch of the liquid crystal. We first review the Landau–de Gennes continuum theory we use in our calculations, in which the orientational order is described by a second-rank tensor and the free energy of a liquid crystal is given as a functional of . We show that a thin film of a chiral liquid crystal can exhibit a diverse variety of ordered structures involving topological line defects (disclination lines), depending on film thickness, temperature, and type of surface anchoring (normal, planar, and planar degenerate). Such exotic structures include a hexagonal lattice of Skyrmions, a whirl-like localized structure that finds in its place in a wide variety of condensed matter systems. A thin film of a chiral liquid crystal thus provides an interesting platform for the investigation of exotic structures of orientational order arising from the frustration between the bulk ordering and the spatial confinement with surface anchoring.","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42302397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-10DOI: 10.1080/21680396.2022.2086932
A. Jákli, Y. Nastishin, O. Lavrentovich
{"title":"Defects in Bent-core Liquid Crystals","authors":"A. Jákli, Y. Nastishin, O. Lavrentovich","doi":"10.1080/21680396.2022.2086932","DOIUrl":"https://doi.org/10.1080/21680396.2022.2086932","url":null,"abstract":"","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45229027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-16DOI: 10.1080/21680396.2022.2076748
B. Zappone, E. Lacaze
. Smectic liquid crystals exhibit a remarkable ability to self-organize into a variety of textures, patterns, and arrays extending over large surface areas with microscale periodicity. These structures provide a useful platform for the bottom-up fabrication of microdevices and functional materials, such as microlens arrays and nanoparticle templates. Periodic structures appear in response to a conflict of director alignment created within the smectic film by external fields such as hybrid (planar-homeotropic) anchoring conditions at the film interfaces or an electric field applied normal to the surface anchoring direction. In this article, we review the formation, structure, and applications of one-dimensional (1d) patterns obtained in response to a director bend, typically induced by unidirectional hybrid anchoring conditions in thin films or under applied electric fields. Compared to lattices of focal conic, 1d patterns harbor an unusual array of topological defects, including disclination and dislocation lines, grain boundaries, and curvature walls, running along periodically spaced and bend-free cylindrical stacks of smectic layers. These defects, most of which have been described by Maurice Kleman, appear to drive the structural evolution of 1d patterns as a function of the film thickness. Under unidirectional hybrid anchoring, the defects are oriented perpendicular to the planar anchoring direction and provide highly anisotropic templates for building ordered networks of close-packed nanoparticles. Moreover, the array formation at the transition from the nematic to the smectic phase is intimately connected to the smectic phase frustration by bend distortions, producing an “intermediate” smectic with partial penetration of the bend distortion through undercooled nematic domains
{"title":"One-dimensional patterns and topological defects in smectic liquid crystal films","authors":"B. Zappone, E. Lacaze","doi":"10.1080/21680396.2022.2076748","DOIUrl":"https://doi.org/10.1080/21680396.2022.2076748","url":null,"abstract":". Smectic liquid crystals exhibit a remarkable ability to self-organize into a variety of textures, patterns, and arrays extending over large surface areas with microscale periodicity. These structures provide a useful platform for the bottom-up fabrication of microdevices and functional materials, such as microlens arrays and nanoparticle templates. Periodic structures appear in response to a conflict of director alignment created within the smectic film by external fields such as hybrid (planar-homeotropic) anchoring conditions at the film interfaces or an electric field applied normal to the surface anchoring direction. In this article, we review the formation, structure, and applications of one-dimensional (1d) patterns obtained in response to a director bend, typically induced by unidirectional hybrid anchoring conditions in thin films or under applied electric fields. Compared to lattices of focal conic, 1d patterns harbor an unusual array of topological defects, including disclination and dislocation lines, grain boundaries, and curvature walls, running along periodically spaced and bend-free cylindrical stacks of smectic layers. These defects, most of which have been described by Maurice Kleman, appear to drive the structural evolution of 1d patterns as a function of the film thickness. Under unidirectional hybrid anchoring, the defects are oriented perpendicular to the planar anchoring direction and provide highly anisotropic templates for building ordered networks of close-packed nanoparticles. Moreover, the array formation at the transition from the nematic to the smectic phase is intimately connected to the smectic phase frustration by bend distortions, producing an “intermediate” smectic with partial penetration of the bend distortion through undercooled nematic domains","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46774195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-14DOI: 10.1080/21680396.2022.2067257
G. P. Alexander, R. Kamien
We review the interpretation of Whitehead products in homotopy theory as an entanglement of topological defects in ordered media.
我们回顾了同伦论中Whitehead乘积作为有序介质中拓扑缺陷的纠缠的解释。
{"title":"Entanglements and Whitehead Products: Generalizing Kleman's Construction to Higher-Dimensional Defects","authors":"G. P. Alexander, R. Kamien","doi":"10.1080/21680396.2022.2067257","DOIUrl":"https://doi.org/10.1080/21680396.2022.2067257","url":null,"abstract":"We review the interpretation of Whitehead products in homotopy theory as an entanglement of topological defects in ordered media.","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44030015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-16DOI: 10.1080/21680396.2022.2042745
Saša Harkai, G. Cordoyiannis, Adam L. Susser, Bryce S. Murray, A. Ferris, B. Rožič, Z. Kutnjak, C. Rosenblatt, S. Kralj
Topological line defects are ubiquitous in nature and appear at all physical scales, including in condensed matter systems, nuclear physics, and cosmology. Particularly useful systems to study line defects are nematic liquid crystals (LCs), where they describe singular or nonsingular frustrations in orientational order and are referred to as disclinations. In nematic LCs, line defects could be relatively simply created, manipulated, and observed. We consider cases where disclinations are stabilized either topologically in plane-parallel confinements or by chirality. In the former case, we report on studies in which defect core transformations are investigated, the intriguing dynamics of strength disclinations in LCs exhibiting negative dielectric anisotropy, and stabilization and manipulation of assemblies of defects. For the case of chiral nematics, we consider nanoparticle-driven stabilization of defect lattices. The resulting line defect assemblies could pave the way to several applications in photonics, sensitive detectors, and information storage devices. These excitations, moreover, have numerous analogs in other branches of physics. Studying their universal properties in nematics could deepen understanding of several phenomena, which are still unresolved at the fundamental level.
{"title":"Manipulation of mechanically nanopatterned line defect assemblies in plane-parallel nematic liquid crystals","authors":"Saša Harkai, G. Cordoyiannis, Adam L. Susser, Bryce S. Murray, A. Ferris, B. Rožič, Z. Kutnjak, C. Rosenblatt, S. Kralj","doi":"10.1080/21680396.2022.2042745","DOIUrl":"https://doi.org/10.1080/21680396.2022.2042745","url":null,"abstract":"Topological line defects are ubiquitous in nature and appear at all physical scales, including in condensed matter systems, nuclear physics, and cosmology. Particularly useful systems to study line defects are nematic liquid crystals (LCs), where they describe singular or nonsingular frustrations in orientational order and are referred to as disclinations. In nematic LCs, line defects could be relatively simply created, manipulated, and observed. We consider cases where disclinations are stabilized either topologically in plane-parallel confinements or by chirality. In the former case, we report on studies in which defect core transformations are investigated, the intriguing dynamics of strength disclinations in LCs exhibiting negative dielectric anisotropy, and stabilization and manipulation of assemblies of defects. For the case of chiral nematics, we consider nanoparticle-driven stabilization of defect lattices. The resulting line defect assemblies could pave the way to several applications in photonics, sensitive detectors, and information storage devices. These excitations, moreover, have numerous analogs in other branches of physics. Studying their universal properties in nematics could deepen understanding of several phenomena, which are still unresolved at the fundamental level.","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48342730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-10DOI: 10.1080/21680396.2022.2040058
Jingyan Wu, I. Smalyukh
Widely known for their uses in displays and electro-optics, liquid crystals are more than just technological marvels. They vividly reveal the topology and structure of various solitonic and singular field configurations, often markedly resembling the ones arising in many field theories and in the areas ranging from particle physics to optics, hard condensed matter and cosmology. In this review, we focus on chiral nematic liquid crystals to show how these experimentally highly accessible systems provide valuable insights into the structure and behavior of fractional, full, and multi-integer two-dimensional skyrmions, dislocations and both abelian and non-abelian defect lines, as well as various three-dimensionally localized, often knotted structures that include hopfions, heliknotons, torons and twistions. We provide comparisons of some of these field configurations with their topological counterparts in chiral magnets, discussing close analogies between these two condensed matter systems.
{"title":"Review: Hopfions, heliknotons, skyrmions, torons and both abelian and nonabelian vortices in chiral liquid crystals","authors":"Jingyan Wu, I. Smalyukh","doi":"10.1080/21680396.2022.2040058","DOIUrl":"https://doi.org/10.1080/21680396.2022.2040058","url":null,"abstract":"Widely known for their uses in displays and electro-optics, liquid crystals are more than just technological marvels. They vividly reveal the topology and structure of various solitonic and singular field configurations, often markedly resembling the ones arising in many field theories and in the areas ranging from particle physics to optics, hard condensed matter and cosmology. In this review, we focus on chiral nematic liquid crystals to show how these experimentally highly accessible systems provide valuable insights into the structure and behavior of fractional, full, and multi-integer two-dimensional skyrmions, dislocations and both abelian and non-abelian defect lines, as well as various three-dimensionally localized, often knotted structures that include hopfions, heliknotons, torons and twistions. We provide comparisons of some of these field configurations with their topological counterparts in chiral magnets, discussing close analogies between these two condensed matter systems.","PeriodicalId":18087,"journal":{"name":"Liquid Crystals Reviews","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2022-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60431256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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