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You R, Kang S, Lee C, Jeon J, Wie JJ, Kim TS, Yoon DK. Programmable Liquid Crystal Defect Arrays via Electric Field Modulation for Mechanically Functional Liquid Crystal Networks. ACS APPLIED MATERIALS & INTERFACES 2021; 13:36253-36261. [PMID: 34310107 DOI: 10.1021/acsami.1c04999] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The arrangement of mesogenic units determines mechanical response of the liquid crystal polymer network (LCN) film to heat. Here, we show an interesting approach to programming three-dimensional patterns of the LCN films with periodic topological defects generated by applying an electric field. The mechanical properties of three representative patterned LCN films were investigated in terms of the arrangement of mesogenic units through tensile testing. Remarkably, it was determined that LCN films showed enhanced toughness and ductility as defects increased in a given area, which is related to the elastic modulus mismatch that mitigates crack propagation. Our platform can also be used to modulate the frictional force of the patterned LCN films by varying the temperature, which can provide insight into the multiplex mechanical properties of LCN films.
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Affiliation(s)
- Ra You
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Sumin Kang
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Republic of Korea
| | - Changjae Lee
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
| | - Jisoo Jeon
- Department of Polymer Science and Engineering, Inha University, Incheon 22212, Republic of Korea
- Program in Environmental and Polymer Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Jeong Jae Wie
- Department of Polymer Science and Engineering, Inha University, Incheon 22212, Republic of Korea
- Program in Environmental and Polymer Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Taek-Soo Kim
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Republic of Korea
| | - Dong Ki Yoon
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
- Graduate School of Nanoscience and Technology and KAIST Institute for Nanocentury, KAIST, Daejeon 34141, Republic of Korea
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Role of Stimuli on Liquid Crystalline Defects: From Defect Engineering to Switchable Functional Materials. MATERIALS 2020; 13:ma13235466. [PMID: 33266312 PMCID: PMC7729749 DOI: 10.3390/ma13235466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 11/17/2022]
Abstract
Achieving tunable physical properties is currently one of the most exciting research topics. In order to realize this goal, a medium that is responsive to external stimuli and can undergo a change in its physical property is required. Liquid crystal (LC) is a prominent candidate, as its physical and optical properties can be easily manipulated with various stimuli, such as surface anchoring, rubbing, geometric confinement, and external fields. Having broken away from the past devotion to obtaining a uniform domain of LCs, people are now putting significant efforts toward forming and manipulating ordered and oriented defect structures with a unique arrangement within. The complicated molecular order with tunability would benefit the interdisciplinary research fields of optics, physics, photonics, and materials science. In this review, the recent progress toward defect engineering in the nematic and smectic phases by controlling the surface environment and electric field and their combinational methods is introduced. We close the review with a discussion of the possible applications enabled using LC defect structures as switchable materials.
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Ma LL, Wu SB, Hu W, Liu C, Chen P, Qian H, Wang Y, Chi L, Lu YQ. Self-Assembled Asymmetric Microlenses for Four-Dimensional Visual Imaging. ACS NANO 2019; 13:13709-13715. [PMID: 31746201 DOI: 10.1021/acsnano.9b07104] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Visual imaging that can extract three-dimensional (3D) space or polarization information on the target is essential in broad sciences and technologies. The simultaneous acquisition of them usually demands expensive equipment and sophisticated operations. Therefore, it is of great significance to exploit convenient approaches for four-dimensional (3D and polarization) visual imaging. Here, we present an efficient solution based on self-assembled asymmetric liquid crystal microlenses, with freely manipulated phase profiles and symmetry-breaking properties. Accordingly, characteristics of multifocal functionality and polarization selectivity are exhibited, along with the underlying mechanisms. Moreover, with a specific sample featured by radially increased unit sizes and azimuthally varied domain orientations, the discriminability of four-dimensional information is extracted in a single snapshot, via referring to the coordinates of the clearest images. Demultiplexing of depth/polarization information is also demonstrated. This work will unlock a variety of revolutionary apparatuses and lighten extensive applications.
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Affiliation(s)
- Ling-Ling Ma
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Sai-Bo Wu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Wei Hu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Chao Liu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Hao Qian
- State Key Laboratory of Materials Oriented Chemical Engineering, College of Materials Science and Engineering , Nanjing Tech University , Nanjing 210009 , China
| | - Yandong Wang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , Suzhou 215123 , China
| | - Lifeng Chi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , Suzhou 215123 , China
| | - Yan-Qing Lu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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Chae H, Lee YH, Yang M, Yoon WJ, Yoon DK, Jeong KU, Song YH, Choi UH, Lee M. Interesting phase behaviors and ion-conducting properties of dicationic N-alkylimidazolium tetrafluoroborate salts. RSC Adv 2019; 9:3972-3978. [PMID: 35518086 PMCID: PMC9060431 DOI: 10.1039/c8ra09208g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/30/2018] [Indexed: 12/04/2022] Open
Abstract
A series of dicationic imidazolium bis(tetrafluoroborate) salts were newly synthesized, and their phase transition behaviors were correlated with thermal, scattering, optical and conductivity results. The bis-imidazolium salts having side-chain lengths of C6-C10 showed plastic crystal mesophases, while a liquid crystal mesophase was formed in the bis-imidazolium salts with long side-chains (C11 and C12). Soft plastic and liquid crystalline phases were also confirmed by wide-angle X-ray diffraction. For the bis-imidazolium salts exhibiting a plastic crystal mesophase, the ionic conductivity suddenly increased at the melting temperature. However, the bis-imidazolium salts with long side-chains showed a slope increase during the liquid crystal-liquid crystal transition.
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Affiliation(s)
- Hyunho Chae
- Department of Chemistry, Kunsan National University 558 Daehak-ro Gunsan South Korea
| | - Yong-Hoon Lee
- Department of Chemistry, Kunsan National University 558 Daehak-ro Gunsan South Korea
| | - Minyong Yang
- Graduate School of Nanoscience and Technology, Korean Advanced Institute of Science and Technology 291 Daehak-ro, Yuseong-gu Daejeon South Korea
| | - Won-Jin Yoon
- Department of Polymer-Nano Science and Technology, Chonbuk National University 567 Baekje-daero, Deokjin-gu Jeonju South Korea
| | - Dong Ki Yoon
- Graduate School of Nanoscience and Technology, Korean Advanced Institute of Science and Technology 291 Daehak-ro, Yuseong-gu Daejeon South Korea
- Department of Chemistry and KINC, Korean Advanced Institute of Science and Technology 291 Daehak-ro, Yuseong-gu Daejeon South Korea
| | - Kwang-Un Jeong
- Department of Polymer-Nano Science and Technology, Chonbuk National University 567 Baekje-daero, Deokjin-gu Jeonju South Korea
| | - Yeon Hwa Song
- Department of Polymer Engineering, Pukyong National University 45 Yongso-ro, Nam-Gu Busan South Korea
| | - U Hyek Choi
- Department of Polymer Engineering, Pukyong National University 45 Yongso-ro, Nam-Gu Busan South Korea
| | - Minjae Lee
- Department of Chemistry, Kunsan National University 558 Daehak-ro Gunsan South Korea
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Han MJ, Wei D, Kim YH, Ahn H, Shin TJ, Clark NA, Walba DM, Yoon DK. Highly Oriented Liquid Crystal Semiconductor for Organic Field-Effect Transistors. ACS CENTRAL SCIENCE 2018; 4:1495-1502. [PMID: 30555901 PMCID: PMC6276037 DOI: 10.1021/acscentsci.8b00465] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Indexed: 06/09/2023]
Abstract
We report a mesogenic compound which introduces nematic liquid crystal (LC) ordering into the benzothienobenzothiophene (BTBT) family of LCs, creating a new class of LC semiconducting materials which respond in a facile way to anisotropic surfaces, and can, thereby, be effectively processed into highly oriented monodomains. Measurement on these domains of the electrical conductivity, with in situ monitoring of domain quality and orientation using LC birefringence textures in electroded cells, brings a new era of precision and reliability to the determination of anisotropic carrier mobility in LC semiconductors.
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Affiliation(s)
- Moon Jong Han
- Graduate
School of Nanoscience and Technology, Korea
Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Dayan Wei
- Department
of Chemistry and Biochemistry, Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
| | - Yun Ho Kim
- Advanced
Functional Materials Research Group, KRICT, Daejeon 34114, Republic of Korea
| | - Hyungju Ahn
- Pohang
Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Tae Joo Shin
- UNIST
Central Research Facilities & School of Natural Science, UNIST, Ulsan 44919, Republic of Korea
| | - Noel A. Clark
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
| | - David M. Walba
- Department
of Chemistry and Biochemistry, Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
| | - Dong Ki Yoon
- Graduate
School of Nanoscience and Technology, Korea
Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Department
of Chemistry and KINC, Korea Advanced Institute
of Science and Technology, Daejeon 34141, Republic of Korea
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Shin MJ, Gim MJ, Yoon DK. Directed Self-Assembly of Topological Defects of Liquid Crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2551-2556. [PMID: 29368930 DOI: 10.1021/acs.langmuir.7b04216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One of the alluring aspects of liquid crystals (LCs) is their readily controllable self-assembly behavior, leading to comprehension of complex topological structures and practical patterning applications. Here, we report on manipulating various kinds of topological defects by adopting an imprinted polymer-based soft microchannel that simultaneously imposes adjustable surface anchoring, confinement, and uniaxial alignment. Distinctive molecular orientation could be achieved by varying the surface anchoring conditions at the sidewall polymer and the rubbing directions on the bottom layer. On this pioneering platform, a common LC material, 8CB (4'-n-octyl-4-cyano-biphenyl), was placed where various topological defect domains were generated in a periodic arrangement. The experimental results showed that our platform can change the packing behavior and even the shape of topological defects by varying the rubbing condition. We believe that this facile tool to modulate surface boundary conditions combined with topographic confinement can open a way to use LC materials in potential optical and patterning applications.
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Affiliation(s)
- Min Jeong Shin
- Graduate School of Nanoscience and Technology and KINC and ‡Department of Chemistry, KAIST , Daejeon 34141, Korea
| | - Min-Jun Gim
- Graduate School of Nanoscience and Technology and KINC and ‡Department of Chemistry, KAIST , Daejeon 34141, Korea
| | - Dong Ki Yoon
- Graduate School of Nanoscience and Technology and KINC and ‡Department of Chemistry, KAIST , Daejeon 34141, Korea
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Busch M, Kityk AV, Piecek W, Hofmann T, Wallacher D, Całus S, Kula P, Steinhart M, Eich M, Huber P. A ferroelectric liquid crystal confined in cylindrical nanopores: reversible smectic layer buckling, enhanced light rotation and extremely fast electro-optically active Goldstone excitations. NANOSCALE 2017; 9:19086-19099. [PMID: 29199756 DOI: 10.1039/c7nr07273b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The orientational and translational order of a thermotropic ferroelectric liquid crystal (2MBOCBC) imbibed in self-organized, parallel, cylindrical pores with radii of 10, 15, or 20 nm in anodic aluminium oxide monoliths (AAO) are explored by high-resolution linear and circular optical birefringence as well as neutron diffraction texture analysis. The results are compared to experiments on the bulk system. The native oxidic pore walls do not provide a stable smectogen wall anchoring. By contrast, a polymeric wall grafting enforcing planar molecular anchoring results in a thermal-history independent formation of smectic C* helices and a reversible chevron-like layer buckling. An enhancement of the optical rotatory power by up to one order of magnitude of the confined compared to the bulk liquid crystal is traced to the pretransitional formation of helical structures at the smectic-A*-to-smectic-C* transformation. A linear electro-optical birefringence effect evidences collective fluctuations in the molecular tilt vector direction along the confined helical superstructures, i.e. the Goldstone phason excitations typical of the para-to-ferroelectric transition. Their relaxation frequencies increase with the square of the inverse pore radii as characteristic of plane-wave excitations and are two orders of magnitude larger than in the bulk, evidencing an exceptionally fast electro-optical functionality of the liquid-crystalline-AAO nanohybrids.
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Affiliation(s)
- Mark Busch
- Institute of Materials Physics and Technology, Hamburg University of Technology, 21073 Hamburg, Germany.
| | - Andriy V Kityk
- Institute of Materials Physics and Technology, Hamburg University of Technology, 21073 Hamburg, Germany. and Faculty of Electrical Engineering, Czestochowa University of Technology, 42-200 Czestochowa, Poland.
| | - Wiktor Piecek
- Military University of Technology, 00-908 Warsaw, Poland
| | - Tommy Hofmann
- Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
| | - Dirk Wallacher
- Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
| | - Sylwia Całus
- Faculty of Electrical Engineering, Czestochowa University of Technology, 42-200 Czestochowa, Poland.
| | | | - Martin Steinhart
- Institute for the Chemistry of New Materials, University Osnabrück, 49067 Osnabrück, Germany
| | - Manfred Eich
- Institute of Optical and Electronic Materials, Hamburg University of Technology, 21073 Hamburg, Germany and Institute of Materials Research, Helmholtz-Zentrum Geesthacht, 21502 Geesthacht, Germany
| | - Patrick Huber
- Institute of Materials Physics and Technology, Hamburg University of Technology, 21073 Hamburg, Germany.
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