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Zhang Z, Deng C, Fan X, Li M, Zhang M, Wang X, Chen F, Shi S, Zhou Y, Deng L, Gao H, Xiong W. 3D Directional Assembly of Liquid Crystal Molecules. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2401533. [PMID: 38794830 DOI: 10.1002/adma.202401533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 05/20/2024] [Indexed: 05/26/2024]
Abstract
The precise construction of hierarchically long-range ordered structures using molecules as fundamental building blocks can fully harness their anisotropy and potential. However, the 3D, high-precision, and single-step directional assembly of molecules is a long-pending challenge. Here, a 3D directional molecular assembly strategy via femtosecond laser direct writing (FsLDW) is proposed and the feasibility of this approach using liquid crystal (LC) molecules as an illustrative example is demonstrated. The physical mechanism for femtosecond (fs) laser-induced assembly of LC molecules is investigated, and precise 3D arbitrary assembly of LC molecules is achieved by defining the discretized laser scanning pathway. Additionally, an LC-based Fresnel zone plate array with polarization selection and colorization imaging functions is fabricated to further illustrate the potential of this method. This study not only introduces a 3D high-resolution alignment method for LC-based functional devices but also establishes a universal protocol for the precise 3D directional assembly of anisotropic molecules.
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Affiliation(s)
- Zexu Zhang
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chunsan Deng
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xuhao Fan
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Minjing Li
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Mingduo Zhang
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xinger Wang
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Fayu Chen
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shaoxi Shi
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yining Zhou
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Leimin Deng
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
| | - Hui Gao
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
| | - Wei Xiong
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
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Large-scale self-organization of reconfigurable topological defect networks in nematic liquid crystals. Nat Commun 2016; 7:13238. [PMID: 27819290 PMCID: PMC5103064 DOI: 10.1038/ncomms13238] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/13/2016] [Indexed: 11/08/2022] Open
Abstract
Topological defects in nematic liquid crystals are ubiquitous. The defects are important in understanding the fundamental properties of the systems, as well as in practical applications, such as colloidal self-assembly, optical vortex generation and templates for molecular self-assembly. Usually, spatially and temporally stable defects require geometrical frustration imposed by surfaces; otherwise, the system relaxes because of the high cost of the elastic energy. So far, multiple defects are kept in bulk nematic liquid crystals by top-down lithographic techniques. In this work, we stabilize a large number of umbilical defects by doping with an ionic impurity. This method does not require pre-patterned surfaces. We demonstrate that molecular reorientation controlled by an AC voltage induces periodic density modulation of ions accumulated at an electrically insulating polymer interface, resulting in self-organization of a two-dimensional square array of umbilical defects that is reconfigurable and tunable. Patterning liquid crystals is essential for their applications in photonics, which is commonly achieved by top-down lithographic approaches. Here, Sasaki et al. show a template-free approach that enables fabricating a large number of ordered square microarrays with tunable lattice on millimetre scale.
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Mirri G, Škarabot M, Muševič I. In situ laser-imprinted surface realignment of a nematic liquid crystal. SOFT MATTER 2015; 11:3347-3353. [PMID: 25790268 DOI: 10.1039/c5sm00282f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a new method for the in-plane realignment of nematic liquid crystals in already fully assembled cells with uni-directionally rubbed polyimide as an aligning layer. We use nematic liquid crystals (NLCs) with a relatively high nematic-isotropic transition temperature and we focus the IR laser beam of the laser tweezers selectively onto one or the other of the inner interfaces. The heat generated by the IR absorption locally melts the liquid crystal and creates an isotropic island with well-defined molecular anchoring at the nematic-isotropic interface. By scanning the laser beam along a pre-defined line, the moving isotropic-nematic interface leaves behind a well oriented LC domain, with LC molecules aligned at 45° to the rubbing direction. If we in addition move the sample with respect to this scanning line, we would be able to selectively realign micro-domains of the liquid crystal with respect to the original alignment induced by the PI rubbing. The realignment can be performed independently on each LC-glass interface, thereby producing predefined domains with customized and controllable alignment within an otherwise uniformly aligned cell.
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Affiliation(s)
- Giorgio Mirri
- Condensed Matter Physics Department, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
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Sai DV, Kumar TA, Haase W, Roy A, Dhara S. Effect of smectic short-range order on the discontinuous anchoring transition in nematic liquid crystals. J Chem Phys 2014; 141:044706. [DOI: 10.1063/1.4890532] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Uehara M, Aya S, Araoka F, Ishikawa K, Takezoe H, Morikawa J. Discontinuous thermal diffusivity change due to the anchoring transition of a liquid crystal on a perfluoropolymer surface. Chemphyschem 2014; 15:1452-6. [PMID: 24677707 DOI: 10.1002/cphc.201300975] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Indexed: 11/08/2022]
Abstract
Thermal diffusivity of a liquid crystal, 4'-butyl-4-heptyl-bicyclohexyl-4-carbonitrile, was measured using a temperature wave method. The liquid crystal was sandwiched by two glass substrates, which were treated with three different surface agents for providing distinct molecular orientations. Here, we demonstrate that: 1) a large thermal diffusivity anisotropy arising from different orientations, that is, planar and homeotropic states, was found in the nematic and smectic A phases; 2) when substrates were coated with a perfluoropolymer, abrupt changes of the thermal diffusivity were observed in the nematic phase both on cooling and heating due to the discontinuous anchoring transition between planar and homeotropic states. The temperature dependence of the thermal diffusivity anisotropy was well described by a power law, with an exponent of 0.27 according to the mean-field theory.
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Affiliation(s)
- Michiru Uehara
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8550 (Japan), Fax: (+81) 3-5734-2497
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Rasna MV, Zuhail KP, Manda R, Paik P, Haase W, Dhara S. Discontinuous anchoring transition and photothermal switching in composites of liquid crystals and conducting polymer nanofibers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:052503. [PMID: 25353811 DOI: 10.1103/physreve.89.052503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Indexed: 06/04/2023]
Abstract
We prepared nanocomposites of a nematic liquid crystal and nanofibers of a conducting polymer (polyaniline). All the nanocomposites exhibit a discontinuous surface anchoring transition from planar to homeotropic in the nematic phase on a perfluoropolymer coated surface with a thermal hysteresis (≈ 5.3 °C). We observe a relatively large bistable conductivity and demonstrate a light driven switching of conductivity and dielectric constant in dye doped nanocomposites in the thermal hysteresis (bistable) region. The experimental results have been explained based on the reorientation of the nanofibers driven by the anchoring transition of the nematic liquid crystal. We show a significant enhancement of the bistable temperature range (≈ 13 °C) by an appropriate choice of compound in the binary system.
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Affiliation(s)
- M V Rasna
- School of Physics, University of Hyderabad, Hyderabad 500046, India
| | - K P Zuhail
- School of Physics, University of Hyderabad, Hyderabad 500046, India
| | - R Manda
- School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046, India
| | - P Paik
- School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046, India
| | - W Haase
- Darmstadt University of Technology, Eduard Zintl Institute for Inorganic and Physical Chemistry, Petersenstrasse 20, Darmstadt 64287, Germany
| | - Surajit Dhara
- School of Physics, University of Hyderabad, Hyderabad 500046, India
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Ji S, Shigeta M, Niko Y, Watanabe J, Konishi GI. Synthesis of highly soluble fluorescent π-extended 2-(2-thienyl)benzothiazole derivatives via oxidative cyclization of 2-thienylthioanilide as the key step. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.10.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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