题名 | Direct Observation of Biaxial Nematic Order in Auxetic Liquid Crystal Elastomers |
作者 | |
通讯作者 | Raistrick, Thomas |
发表日期 | 2023-01
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DOI | |
发表期刊 | |
EISSN | 1996-1944
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卷号 | 16期号:1 |
摘要 | Auxetic materials exhibit a negative Poisson’s ratio, i.e., they become thicker rather than thinner in at least one dimension when strained. Recently, a nematic liquid crystal elastomer (LCE) was shown to be the first synthetic auxetic material at a molecular level. Understanding the mechanism of the auxetic response in LCEs is clearly important, and it has been suggested through detailed Raman scattering studies that it is related to the reduction of uniaxial order and emergence of biaxial order on strain. In this paper, we demonstrate direct observation of the biaxial order in an auxetic LCE under strain. We fabricated ~100 μm thick LCE strips with complementary geometries, exhibiting either planar or homeotropic alignment, in which the auxetic response is seen in the thickness or width of the sample, respectively. Polarized Raman scattering measurements on the planar sample show directly the reduction in the uniaxial order parameters on strain and suggest the emergence of biaxial order to mediate the auxetic response in the sample thickness. The homeotropic sample is studied via conoscopy, allowing direct observation of both the auxetic response in the width of the sample and increasing biaxiality in the LCE as it is strained. We verified that the mechanism of the auxetic response in auxetic LCEs is due to the emergence of the biaxial order and conclude such materials can be added to the small number of biaxial nematic systems that have been observed. Importantly, we also show that the mechanical Frèedericksz transition seen in some LCEs is consistent with a strain-induced transition from an optically positive to an optically negative biaxial system under strain, rather than a director rotation in a uniaxial system. © 2022 by the authors. |
相关链接 | [来源记录] |
收录类别 | |
语种 | 英语
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学校署名 | 其他
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资助项目 | This research was funded by the Engineering and Physical Sciences Research Council (EPSRC EP/V054724/1).
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WOS研究方向 | Chemistry
; Materials Science
; Metallurgy & Metallurgical Engineering
; Physics
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WOS类目 | Chemistry, Physical
; Materials Science, Multidisciplinary
; Metallurgy & Metallurgical Engineering
; Physics, Applied
; Physics, Condensed Matter
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WOS记录号 | WOS:000908975500001
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出版者 | |
EI入藏号 | 20230213360275
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EI主题词 | Elastomers
; Nematic liquid crystals
; Plastics
|
EI分类号 | Light/Optics:741.1
; Polymer Products:817.1
; Elastomers:818.2
|
来源库 | EV Compendex
|
引用统计 |
被引频次[WOS]:7
|
成果类型 | 期刊论文 |
条目标识符 | http://sustech.caswiz.com/handle/2SGJ60CL/519746 |
专题 | 工学院_电子与电气工程系 |
作者单位 | 1.School of Physics and Astronomy, University of Leeds, Leeds; LS2 9JT, United Kingdom 2.Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen; 518055, China |
第一作者单位 | 电子与电气工程系 |
推荐引用方式 GB/T 7714 |
Wang, Zhenming,Raistrick, Thomas,Street, Aidan,et al. Direct Observation of Biaxial Nematic Order in Auxetic Liquid Crystal Elastomers[J]. Materials,2023,16(1).
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APA |
Wang, Zhenming,Raistrick, Thomas,Street, Aidan,Reynolds, Matthew,Liu, Yanjun,&Gleeson, Helen F..(2023).Direct Observation of Biaxial Nematic Order in Auxetic Liquid Crystal Elastomers.Materials,16(1).
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MLA |
Wang, Zhenming,et al."Direct Observation of Biaxial Nematic Order in Auxetic Liquid Crystal Elastomers".Materials 16.1(2023).
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条目包含的文件 | 条目无相关文件。 |
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