1
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Wang J, Wen Y, Pan D, Lin S, Chinnappan A, He Q, Liu C, Huang Z, Cai S, Ramakrishna S, Shin S. High Thermal Conductive Liquid Crystal Elastomer Nanofibers. NANO LETTERS 2024; 24:9990-9997. [PMID: 39101516 DOI: 10.1021/acs.nanolett.4c02752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Liquid crystal elastomers (LCEs), consisting of polymer networks and liquid crystal mesogens, show a reversible phase change under thermal stimuli. However, the kinetic performance is limited by the inherently low thermal conductivity of the polymers. Transforming amorphous bulk into a fiber enhances thermal conductivity through the alignment of polymer chains. Challenges are present due to their rigid networks, while cross-links are crucial for deformation. Here, we employ hydrodynamic alignment to orient the LCE domains assisted by controlled in situ cross-linking and to remarkably reduce the diameter to submicrons. We report that the intrinsic thermal conductivity of LCE fibers at room temperature reaches 1.44 ± 0.32 W/m-K with the sub-100 nm diameter close to the upper limit determined in the quasi-1D regime. Combining the outstanding thermal conductivity and thin diameters, we anticipate these fibers to exhibit a rapid response and high force output in thermomechanical systems. The fabrication method is expected to apply to other cross-linked polymers.
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Affiliation(s)
- Jingxuan Wang
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Yue Wen
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Duo Pan
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education; National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China
| | - Shulang Lin
- Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Amutha Chinnappan
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Qiguang He
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin 999077, Hong Kong, China
| | - Chuntai Liu
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education; National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China
| | - Zhiwei Huang
- Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States of America
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Sunmi Shin
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
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2
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Tang C. Fundamental Aspects of Stretchable Mechanochromic Materials: Fabrication and Characterization. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3980. [PMID: 39203158 PMCID: PMC11355797 DOI: 10.3390/ma17163980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/08/2024] [Accepted: 08/08/2024] [Indexed: 09/03/2024]
Abstract
Mechanochromic materials provide optical changes in response to mechanical stress and are of interest in a wide range of potential applications such as strain sensing, structural health monitoring, and encryption. Advanced manufacturing such as 3D printing enables the fabrication of complex patterns and geometries. In this work, classes of stretchable mechanochromic materials that provide visual color changes when tension is applied, namely, dyes, polymer dispersed liquid crystals, liquid crystal elastomers, cellulose nanocrystals, photonic nanostructures, hydrogels, and hybrid systems (combinations of other classes) are reviewed. For each class, synthesis and processing, as well as the mechanism of color change are discussed. To enable materials selection across the classes, the mechanochromic sensitivity of the different classes of materials are compared. Photonic systems demonstrate high mechanochromic sensitivity (Δnm/% strain), large dynamic color range, and rapid reversibility. Further, the mechanochromic behavior can be predicted using a simple mechanical model. Photonic systems with a wide range of mechanical properties (elastic modulus) have been achieved. The addition of dyes to photonic systems has broadened the dynamic range, i.e., the strain over which there is an optical change. For applications in which irreversible color change is desired, dye-based systems or liquid crystal elastomer systems can be formulated. While many promising applications have been demonstrated, manufacturing uniform color on a large scale remains a challenge. Standardized characterization methods are needed to translate materials to practical applications. The sustainability of mechanochromic materials is also an important consideration.
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Affiliation(s)
- Christina Tang
- Chemical and Life Science Engineering Department, Virginia Commonwealth University, Richmond, VA 23284, USA
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3
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Wang J, Zhou Z, Li X, Chang C. Cellulose nanocrystals-based optical organohydrogel fiber with customizable iridescent colors for strain and humidity response. Int J Biol Macromol 2024; 275:133501. [PMID: 38960229 DOI: 10.1016/j.ijbiomac.2024.133501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 06/18/2024] [Accepted: 06/26/2024] [Indexed: 07/05/2024]
Abstract
Stimuli-responsive optical hydrogels are widely used in various fields including environmental sensing, optical encryption, and intelligent display manufacturing. However, these hydrogels are susceptible to water losses when exposed to air, leading to structural damage, significantly shortened service lives, and compromised durability. This study presents mechanically robust, environmentally stable, and multi-stimuli responsive optical organohydrogel fibers with customizable iridescent colors. These fibers are fabricated by incorporating tunicate cellulose nanocrystals, alginate, and acrylamide in a glycerol-water binary system. The synthesized fibers exhibit high strength (1.38 MPa), moisture retention capabilities, and elastic properties. Furthermore, a sensor based on these fibers demonstrates high- and low-temperature resistance along with stimuli-responsive characteristics, effectively detecting changes in environmental humidity and strains. Moreover, the fiber sensor demonstrates continuous, repeatable, and quantitatively predictable moisture discoloration responses across a humidity range of 11 % and 98 %. During strain sensing, the optical-organohydrogel-based sensor demonstrates a large working strain (50 %) and excellent cycling stability, underscoring its potential for effectively monitoring a wide range of intricate human motions. Overall, the synthesized fibers and their simple fabrication method can elicit new avenues for numerous related applications including the large-scale implementation of advanced wearable technology.
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Affiliation(s)
- Junmei Wang
- Engineering Research Center of Bamboo Advanced Materials and Conversion of Jiangxi Province, School of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou 341000, PR China.
| | - Zhimin Zhou
- Engineering Research Center of Bamboo Advanced Materials and Conversion of Jiangxi Province, School of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou 341000, PR China
| | - Xingxing Li
- Engineering Research Center of Bamboo Advanced Materials and Conversion of Jiangxi Province, School of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou 341000, PR China
| | - Chunyu Chang
- College of Chemistry and Molecular Sciences, Hubei Engineering Center of Natural Polymer-based Medical Materials, Wuhan University, Wuhan 430072, China.
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4
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Zhang J, Zhang Y, Yang J, Wang X. Beyond Color Boundaries: Pioneering Developments in Cholesteric Liquid Crystal Photonic Actuators. MICROMACHINES 2024; 15:808. [PMID: 38930778 PMCID: PMC11205596 DOI: 10.3390/mi15060808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/09/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024]
Abstract
Creatures in nature make extensive use of structural color adaptive camouflage to survive. Cholesteric liquid crystals, with nanostructures similar to those of natural organisms, can be combined with actuators to produce bright structural colors in response to a wide range of stimuli. Structural colors modulated by nano-helical structures can continuously and selectively reflect specific wavelengths of light, breaking the limit of colors recognizable by the human eye. In this review, the current state of research on cholesteric liquid crystal photonic actuators and their technological applications is presented. First, the basic concepts of cholesteric liquid crystals and their nanostructural modulation are outlined. Then, the cholesteric liquid crystal photonic actuators responding to different stimuli (mechanical, thermal, electrical, light, humidity, magnetic, pneumatic) are presented. This review describes the practical applications of cholesteric liquid crystal photonic actuators and summarizes the prospects for the development of these advanced structures as well as the challenges and their promising applications.
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Affiliation(s)
- Jinying Zhang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314001, China
| | - Yexiaotong Zhang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
| | - Jiaxing Yang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
| | - Xinye Wang
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China; (Y.Z.); (J.Y.); (X.W.)
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5
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Tian X, Guo Y, Zhang J, Ivasishin OM, Jia J, Yan J. Fiber Actuators Based on Reversible Thermal Responsive Liquid Crystal Elastomer. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306952. [PMID: 38175860 DOI: 10.1002/smll.202306952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/16/2023] [Indexed: 01/06/2024]
Abstract
Soft actuators inspired by the movement of organisms have attracted extensive attention in the fields of soft robotics, electronic skin, artificial intelligence, and healthcare due to their excellent adaptability and operational safety. Liquid crystal elastomer fiber actuators (LCEFAs) are considered as one of the most promising soft actuators since they can provide reversible linear motion and are easily integrated or woven into complex structures to perform pre-programmed movements such as stretching, rotating, bending, and expanding. The research on LCEFAs mainly focuses on controllable preparation, structural design, and functional applications. This review, for the first time, provides a comprehensive and systematic review of recent advances in this important field by focusing on reversible thermal response LCEFAs. First, the thermal driving mechanism, and direct and indirect heating strategies of LCEFAs are systematically summarized and analyzed. Then, the fabrication methods and functional applications of LCEFAs are summarized and discussed. Finally, the challenges and technical difficulties that may hinder the performance improvement and large-scale production of LCEFAs are proposed, and the development opportunities of LCEFAs are prospected.
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Affiliation(s)
- Xuwang Tian
- College of Materials Science and Engineering, Key Laboratory of Automobile Materials Ministry of Education, Jilin University, Changchun, 130012, China
| | - Yongshi Guo
- College of Textile, Donghua University, Shanghai, 201620, China
| | - Jiaqi Zhang
- College of Materials Science and Engineering, Key Laboratory of Automobile Materials Ministry of Education, Jilin University, Changchun, 130012, China
| | - Orest M Ivasishin
- College of Materials Science and Engineering, Key Laboratory of Automobile Materials Ministry of Education, Jilin University, Changchun, 130012, China
| | - Jiru Jia
- School of Textile Garment and Design, Changshu Institute of Technology, Suzhou, Jiangsu, 215500, China
| | - Jianhua Yan
- College of Textile, Donghua University, Shanghai, 201620, China
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6
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Jiaqi Y, Zhixiang W, Sirui C, Qiongya L, Yi Q, Hao W, Yuxiao H, Zhang F, Qing G. Large-scale production of chiral nematic microspheres. Chem Commun (Camb) 2024; 60:5856-5859. [PMID: 38752695 DOI: 10.1039/d4cc00120f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The membrane emulsification technique enables the self-assembly of cellulose nanocrystals (CNCs) confined within a spherical geometry for large-scale production. The resulting solid microspheres show long-range ordering with chiral nematic structures, and this fascinating hierarchical architecture can even be transferred to mesoporous carbon or silica microparticles by a sacrificial template method.
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Affiliation(s)
- Yu Jiaqi
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Wang Zhixiang
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Chen Sirui
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Li Qiongya
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Qian Yi
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Wang Hao
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Huang Yuxiao
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Fusheng Zhang
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Guangyan Qing
- Hubei Key Laboratory of Biomass Fibers and Eco-dyeing & Finishing, College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
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7
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Sun Y, Men Y, Liu S, Wang X, Li C. Liquid crystalline elastomer self-oscillating fiber actuators fabricated from soft tubular molds. SOFT MATTER 2024; 20:4246-4256. [PMID: 38747973 DOI: 10.1039/d4sm00134f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The self-oscillation of objects that perform continuous and periodic motions upon unchanging and constant stimuli is highly important for intelligent actuators, advanced robotics, and biomedical machines. Liquid crystalline elastomer (LCE) materials are superior to traditional stimuli-responsive polymeric materials in the development of self-oscillators because of their reversible, large and anisotropic shape-changing ability, fast response ability and versatile structural design. In addition, fiber-shaped oscillators have attracted much interest due to their agility, flexibility and diverse oscillation modes. Herein, we present a strategy for fabricating fiber-shaped LCE self-oscillators using soft tubes as molds. Through the settlement of different configuration states of the soft tubes, the prepared fiber-shaped LCE oscillators can perform continuous rotational self-oscillation or up-and-down shifting self-oscillation under constant light stimuli, which are realized by photoinduced repetitive self-winding motion and self-waving motion, respectively. The mechanism of self-oscillating movements is attributed to the local temperature oscillation of LCE fibers caused by repetitive self-shadowing effects. LCE self-oscillators can operate stably over many oscillating cycles without obvious performance attenuation, revealing good robustness. Our work offers a versatile way by which LCE self-oscillators can be conveniently designed and fabricated in bulk and at low cost, and broadens the road for developing self-oscillating materials for biological robotics and health care machines.
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Affiliation(s)
- Yuying Sun
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Yanli Men
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Shiyu Liu
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Xiuxiu Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Chensha Li
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
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8
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Nam S, Jung W, Shin JH, Choi SS. Omnidirectional color wavelength tuning of stretchable chiral liquid crystal elastomers. LIGHT, SCIENCE & APPLICATIONS 2024; 13:114. [PMID: 38773092 PMCID: PMC11109264 DOI: 10.1038/s41377-024-01470-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/12/2024] [Accepted: 05/07/2024] [Indexed: 05/23/2024]
Abstract
Wavelength-tunable structural colors using stimuli-responsive materials, such as chiral liquid crystals (CLCs), have attracted increasing attention owing to their high functionality in various tunable photonic applications. Ideally, on-demand omnidirectional wavelength control is highly desirable from the perspective of wavelength-tuning freedom. However, despite numerous previous research efforts on tunable CLC structural colors, only mono-directional wavelength tuning toward shorter wavelengths has been employed in most studies to date. In this study, we report the ideally desired omnidirectional wavelength control toward longer and shorter wavelengths with significantly improved tunability over a broadband wavelength range. By using areal expanding and contractive strain control of dielectric elastomer actuators (DEAs) with chiral liquid crystal elastomers (CLCEs), simultaneous and omnidirectional structural color-tuning control was achieved. This breakthrough in omnidirectional wavelength control enhances the achievable tuning freedom and versatility, making it applicable to a broad range of high-functional photonic applications.
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Affiliation(s)
- Seungmin Nam
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Wontae Jung
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Jun Hyuk Shin
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Su Seok Choi
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
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9
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de Castro LC, Engels TAP, Oliveira ON, Schenning APHJ. Sticky Multicolor Mechanochromic Labels. ACS APPLIED MATERIALS & INTERFACES 2024; 16:14144-14151. [PMID: 38448425 PMCID: PMC10958449 DOI: 10.1021/acsami.3c19420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/14/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
Sticky-colored labels are an efficient way to communicate visual information. However, most labels are static. Here, we propose a new category of dynamic sticky labels that change structural colors when stretched. The sticky mechanochromic labels can be pasted on flexible surfaces such as fabric and rubber or even on brittle materials. To enhance their applicability, we demonstrate a simple method for imprinting structural color patterns that are either always visible or reversibly revealed or concealed upon mechanical deformation. The mechanochromic patterns are imprinted with a photomask during the ultraviolet (UV) cross-linking of acrylate-terminated cholesteric liquid crystal oligomers in a single step at room temperature. The photomask locally controls the cross-linking degree and volumetric response of the cholesteric liquid crystal elastomers (CLCEs). A nonuniform thickness change induced by the Poisson's ratio contrast between the pattern and the surrounding background might lead to a color-separation effect. Our sticky multicolor mechanochromic labels may be utilized in stress-strain sensing, building environments, smart clothing, security labels, and decoration.
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Affiliation(s)
- Lucas
D. C. de Castro
- São
Carlos Institute of Physics, University
of São Paulo, São
Carlos 13566-590, SP, Brazil
- Laboratory
of Stimuli-responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology, Eindhoven5612 MB, The Netherlands
| | - Tom A. P. Engels
- Processing
and Performance of Materials, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
| | - Osvaldo N. Oliveira
- São
Carlos Institute of Physics, University
of São Paulo, São
Carlos 13566-590, SP, Brazil
| | - Albert P. H. J. Schenning
- Laboratory
of Stimuli-responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology, Eindhoven5612 MB, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, Eindhoven 5612 MB, The Netherlands
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10
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Cooper EJ, Reynolds M, Raistrick T, Berrow SR, Jull EIL, Reshetnyak V, Mistry D, Gleeson HF. Controlling the Optical Properties of Transparent Auxetic Liquid Crystal Elastomers. Macromolecules 2024; 57:2030-2038. [PMID: 38495386 PMCID: PMC10938889 DOI: 10.1021/acs.macromol.3c02226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/16/2024] [Accepted: 01/30/2024] [Indexed: 03/19/2024]
Abstract
Determining the tunability of the optical coefficients, order parameter, and transition temperatures in optically transparent auxetic liquid crystal elastomers (LCEs) is vital for applications, including impact-resistant glass laminates. Here, we report measurements of the refractive indices, order parameters, and transition temperatures in a family of acrylate-based LCEs in which the mesogenic content varies from ∼50 to ∼85%. Modifications in the precursor mixture allow the order parameter, ⟨P2⟩, of the LCE to be adjusted from 0.46 to 0.73. The extraordinary refractive index changes most significantly with composition, from ∼1.66 to ∼1.69, in moving from a low to high mesogenic content. We demonstrate that all LCE refractive indices decrease with increasing temperature, with temperature coefficients of ∼10-4 K-1, comparable to optical plastics. In these LCEs, the average refractive index and the refractive index anisotropy are tunable via both chemical composition and order parameter control; we report design rules for both.
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Affiliation(s)
- Emily J. Cooper
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Matthew Reynolds
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Thomas Raistrick
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Stuart R. Berrow
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Ethan I. L. Jull
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Victor Reshetnyak
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
- Taras
Shevchenko National University of Kyiv, Kyiv 03680, Ukraine
| | - Devesh Mistry
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
| | - Helen F. Gleeson
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, United
Kingdom
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