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Sadati M, Martinez-Gonzalez JA, Zhou Y, Qazvini NT, Kurtenbach K, Li X, Bukusoglu E, Zhang R, Abbott NL, Hernandez-Ortiz JP, de Pablo JJ. Prolate and oblate chiral liquid crystal spheroids. SCIENCE ADVANCES 2020; 6:eaba6728. [PMID: 32832603 PMCID: PMC7439570 DOI: 10.1126/sciadv.aba6728] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/28/2020] [Indexed: 05/15/2023]
Abstract
Liquid crystals are known to exhibit intriguing textures and color patterns, with applications in display and optical technologies. This work focuses on chiral materials and examines the palette of morphologies that arises when microdroplets are deformed into nonspherical shapes in a controllable manner. Specifically, geometrical confinement and mechanical strain are used to manipulate orientational order, phase transitions, and topological defects that arise in chiral liquid crystal droplets. Inspired by processes encountered in nature, where insects and animals often rely on strain and temperature to alter the optical appearance of dispersed liquid crystalline elements, chiral droplets are dispersed in polymer films and deformation induced by uniaxial or biaxial stretching. Our measurements are interpreted by resorting to simulations of the corresponding systems, thereby providing an in-depth understanding of the morphologies that arise in these materials. The reported structures and assemblies offer potential for applications in smart coatings, smart fabrics, and wearable sensors.
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Affiliation(s)
- Monirosadat Sadati
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA
| | - Jose A. Martinez-Gonzalez
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Parque Chapultepec 1570, San Luis Potosí 78295, SLP, México
| | - Ye Zhou
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Nader Taheri Qazvini
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Chemical Engineering, Swearingen Engineering Center, University of South Carolina, Columbia, SC 29208, USA
| | - Khia Kurtenbach
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Xiao Li
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203, USA
| | - Emre Bukusoglu
- Chemical Engineering Department, Middle East Technical University, Ankara 06800, Turkey
| | - Rui Zhang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Nicholas L. Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Juan Pablo Hernandez-Ortiz
- Departamento de Materiales y Minerales, Facultad de Minas, Universidad Nacional de Colombia, Sede Medellín, Calle 75 # 79A-51, Bloque M17, Medellín, Colombia
| | - Juan J. de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL 60439, USA
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Sadati M, Ramezani-Dakhel H, Bu W, Sevgen E, Liang Z, Erol C, Rahimi M, Taheri Qazvini N, Lin B, Abbott NL, Roux B, Schlossman ML, de Pablo JJ. Molecular Structure of Canonical Liquid Crystal Interfaces. J Am Chem Soc 2017; 139:3841-3850. [PMID: 28177227 DOI: 10.1021/jacs.7b00167] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Numerous applications of liquid crystals rely on control of molecular orientation at an interface. However, little is known about the precise molecular structure of such interfaces. In this work, synchrotron X-ray reflectivity measurements, accompanied by large-scale atomistic molecular dynamics simulations, are used for the first time to reconstruct the air-liquid crystal interface of a nematic material, namely, 4-pentyl-4'-cyanobiphenyl (5CB). The results are compared to those for 4-octyl-4'-cyanobiphenyl (8CB) which, in addition to adopting isotropic and nematic states, can also form a smectic phase. Our findings indicate that the air interface imprints a highly ordered structure into the material; such a local structure then propagates well into the bulk of the liquid crystal, particularly for nematic and smectic phases.
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Affiliation(s)
| | | | | | | | - Zhu Liang
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Cem Erol
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | | | | | | | - Nicholas L. Abbott
- Department
of Chemical and Biological Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | | | - Mark L. Schlossman
- Department
of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Juan J. de Pablo
- Argonne National Laboratory, Argonne, Illinois 60439, United States
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