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Wang KF, Wang BL. Is there only one equilibrium configuration for spontaneous bending of liquid crystal elastomer circular plates with free edges? THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:124. [PMID: 34617149 DOI: 10.1140/epje/s10189-021-00126-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
In this paper, the spontaneous bending of a liquid crystal elastomer (LCE) circular plate under light illumination is investigated. The large bending deformation configurations for the LCE circular plate with free edges are obtained by minimizing the potential energy. It is found that for an LCE circular plate with random distribution of liquid crystal molecules, if the light intensity is small, there is only one equilibrium configuration for bending of the LCE circular plate. However, when the light intensity reaches a critical value, the circular plate will buckle and there will be three possible equilibrium configurations. On the other hand, for an LCE circular plate with uniform orientation of liquid crystal molecules, the strain induced by light is anisotropic, and there is only one equilibrium configuration. In addition, bending shapes of the LCE circular plate depend on its thickness. These results may be useful for designing light-driven LCE devices.
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Affiliation(s)
- K F Wang
- School of Science, Harbin Institute of Technology, Shenzhen, 518055, China.
| | - B L Wang
- School of Science, Harbin Institute of Technology, Shenzhen, 518055, China
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Soltani M, Raahemifar K, Nokhosteen A, Kashkooli FM, Zoudani EL. Numerical Methods in Studies of Liquid Crystal Elastomers. Polymers (Basel) 2021; 13:1650. [PMID: 34069440 PMCID: PMC8159147 DOI: 10.3390/polym13101650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 01/24/2023] Open
Abstract
Liquid crystal elastomers (LCEs) are a type of material with specific features of polymers and of liquid crystals. They exhibit interesting behaviors, i.e., they are able to change their physical properties when met with external stimuli, including heat, light, electric, and magnetic fields. This behavior makes LCEs a suitable candidate for a variety of applications, including, but not limited to, artificial muscles, optical devices, microscopy and imaging systems, biosensor devices, and optimization of solar energy collectors. Due to the wide range of applicability, numerical models are needed not only to further our understanding of the underlining mechanics governing LCE behavior, but also to enable the predictive modeling of their behavior under different circumstances for different applications. Given that several mainstream methods are used for LCE modeling, viz. finite element method, Monte Carlo and molecular dynamics, and the growing interest and reliance on computer modeling for predicting the opto-mechanical behavior of complex structures in real world applications, there is a need to gain a better understanding regarding their strengths and weaknesses so that the best method can be utilized for the specific application at hand. Therefore, this investigation aims to not only to present a multitude of examples on numerical studies conducted on LCEs, but also attempts at offering a concise categorization of different methods based on the desired application to act as a guide for current and future research in this field.
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Affiliation(s)
- Madjid Soltani
- Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran 19991-43344, Iran; (F.M.K.); (E.L.Z.)
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada
- Centre for Biotechnology and Bioengineering (CBB), University of Waterloo, Waterloo, ON N2L 3G1, Canada
- School of Optometry and Vision Science, Faculty of Science, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1, Canada;
- Advanced Bioengineering Initiative Center, Computational Medicine Center, K.N. Toosi University of Technology, Tehran 19991-43344, Iran
| | - Kaamran Raahemifar
- School of Optometry and Vision Science, Faculty of Science, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1, Canada;
- College of Information Sciences and Technology (IST), Data Science and Artificial Intelligence Program, Penn State University, State College, Pennsylvania, PA 16801, USA
- Department of Chemical Engineering, Faculty of Engineering, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1, Canada
| | - Arman Nokhosteen
- Department of Civil and Mechanical Engineering, University of Missouri-Kansas City, Kansas City, MO 64110, USA;
| | - Farshad Moradi Kashkooli
- Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran 19991-43344, Iran; (F.M.K.); (E.L.Z.)
| | - Elham L. Zoudani
- Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran 19991-43344, Iran; (F.M.K.); (E.L.Z.)
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Visschers FLL, Hendrikx M, Zhan Y, Liu D. Liquid crystal polymers with motile surfaces. SOFT MATTER 2018; 14:4898-4912. [PMID: 29892763 DOI: 10.1039/c8sm00524a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In analogy with developments in soft robotics it is anticipated that soft robotic functions at surfaces of objects may have a large impact on human life with respect to comfort, health, medical care and energy. In this review, we demonstrate the possibilities and versatilities of liquid crystal networks and elastomers being explored for soft robotics, with an emphasis on motile surface properties, such as topographical dynamics. Typically the surfaces reversibly transfer from a flat state to a pre-designed corrugated state under various stimuli. But also reversible conversion between different corrugated states is feasible. Generally, the driving triggers are heat, light, electricity or contact with pH changing media. Also, the macroscopic effects of those dynamic topographies, such as altering the friction, wettability and/or performing work are illustrated. The review concludes with the existing challenges as well as outlook opportunities.
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Affiliation(s)
- Fabian L L Visschers
- Laboratory of Functional Organic Materials & Devices, Department of Chemical Engineering & Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands.
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Liu L, Liu MH, Deng LL, Lin BP, Yang H. Near-Infrared Chromophore Functionalized Soft Actuator with Ultrafast Photoresponsive Speed and Superior Mechanical Property. J Am Chem Soc 2017; 139:11333-11336. [DOI: 10.1021/jacs.7b06410] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Li Liu
- School of Chemistry and Chemical
Engineering, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical
Research, Jiangsu Key Laboratory for Science and Application of Molecular
Ferroelectrics, State Key Laboratory of Bioelectronics, Southeast University, Nanjing 211189, China
| | - Mei-Hua Liu
- School of Chemistry and Chemical
Engineering, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical
Research, Jiangsu Key Laboratory for Science and Application of Molecular
Ferroelectrics, State Key Laboratory of Bioelectronics, Southeast University, Nanjing 211189, China
| | - Lin-Lin Deng
- School of Chemistry and Chemical
Engineering, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical
Research, Jiangsu Key Laboratory for Science and Application of Molecular
Ferroelectrics, State Key Laboratory of Bioelectronics, Southeast University, Nanjing 211189, China
| | - Bao-Ping Lin
- School of Chemistry and Chemical
Engineering, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical
Research, Jiangsu Key Laboratory for Science and Application of Molecular
Ferroelectrics, State Key Laboratory of Bioelectronics, Southeast University, Nanjing 211189, China
| | - Hong Yang
- School of Chemistry and Chemical
Engineering, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical
Research, Jiangsu Key Laboratory for Science and Application of Molecular
Ferroelectrics, State Key Laboratory of Bioelectronics, Southeast University, Nanjing 211189, China
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5
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Doi H, Urayama K. Thermal bending coupled with volume change in liquid crystal gels. SOFT MATTER 2017; 13:4341-4348. [PMID: 28440387 DOI: 10.1039/c7sm00602k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigate the thermal bending behavior of liquid crystal gels with hybrid alignment (H-LCGs) accompanied by volume change in isotropic and nematic solvents. The curvature (r-1) of H-LCGs in each solvent markedly depends on the temperature (T) in the nematic state including the reversal of the bending direction, as in the case of the corresponding elastomers in the dry state (H-LCE). The thermal bending of three systems-H-LCGs in isotropic and nematic solvents and H-LCE-differs significantly in several aspects including the T range where r-1 depends on T and the total variation of r-1. The differences in these features among the three systems result from the differences in the magnitude as well as the T-dependence of the nematic order (S), which is correlated with the T-induced volume change. We demonstrate that the T-dependence of the reduced curvature in each system is satisfactorily described by a combination of linear bending theory and the anisotropic Gaussian network model using the corresponding S-T data.
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Affiliation(s)
- Haruka Doi
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Kenji Urayama
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
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Wang M, Sayed SM, Guo LX, Lin BP, Zhang XQ, Sun Y, Yang H. Multi-Stimuli Responsive Carbon Nanotube Incorporated Polysiloxane Azobenzene Liquid Crystalline Elastomer Composites. Macromolecules 2016. [DOI: 10.1021/acs.macromol.5b02388] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Meng Wang
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Sayed Mir Sayed
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Ling-Xiang Guo
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Bao-Ping Lin
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Xue-Qin Zhang
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Ying Sun
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
| | - Hong Yang
- School of Chemistry and Chemical Engineering, Jiangsu
Province Hi-Tech Key Laboratory for Bio-medical Research, Jiangsu
Optoelectronic Functional Materials and Engineering Laboratory, Southeast University, Nanjing, 211189, China
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White TJ, Broer DJ. Programmable and adaptive mechanics with liquid crystal polymer networks and elastomers. NATURE MATERIALS 2015; 14:1087-98. [PMID: 26490216 DOI: 10.1038/nmat4433] [Citation(s) in RCA: 718] [Impact Index Per Article: 79.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/26/2015] [Indexed: 05/22/2023]
Abstract
Liquid crystals are the basis of a pervasive technology of the modern era. Yet, as the display market becomes commoditized, researchers in industry, government and academia are increasingly examining liquid crystalline materials in a variety of polymeric forms and discovering their fascinating and useful properties. In this Review, we detail the historical development of liquid crystalline polymeric materials, with emphasis on the thermally and photogenerated macroscale mechanical responses--such as bending, twisting and buckling--and on local-feature development (primarily related to topographical control). Within this framework, we elucidate the benefits of liquid crystallinity and contrast them with other stimuli-induced mechanical responses reported for other materials. We end with an outlook of existing challenges and near-term application opportunities.
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Affiliation(s)
- Timothy J White
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Dirk J Broer
- Eindhoven University of Technology, Institute for Complex Molecular Systems, Department of Chemical Engineering and Chemistry, Helix Building STO 0.34, PO Box 513, 5600 MB Eindhoven, The Netherlands
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He LH. Response of constrained glassy splay-bend and twist nematic sheets to light and heat. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:83. [PMID: 23921449 DOI: 10.1140/epje/i2013-13083-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 06/09/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
A general approach is proposed to analyze the complex photo- or thermo-response of glassy splay-bend and twist nematic sheets with boundary constraints. The governing equations are two-dimensional, as in the classical plate theory. However, the solution can generate exact three-dimensional displacement and stress distributions within the interior of the sheets, except the boundary layer whose width is of the same order of the sheet thickness.
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Affiliation(s)
- L H He
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, 230026 Hefei, Anhui, P.R. China.
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Lee KM, Tabiryan NV, Bunning TJ, White TJ. Photomechanical mechanism and structure-property considerations in the generation of photomechanical work in glassy, azobenzene liquid crystal polymer networks. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm14017e] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sellinger AT, Wang DH, Tan LS, Vaia RA. Electrothermal polymer nanocomposite actuators. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:3430-3435. [PMID: 20354975 DOI: 10.1002/adma.200904107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Warner M, Modes CD, Corbett D. Curvature in nematic elastica responding to light and heat. Proc Math Phys Eng Sci 2010. [DOI: 10.1098/rspa.2010.0135] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nematic elastic bodies can develop a gradient of response to heat, light and other stimuli. They then bend and develop curvature in a complex manner depending on director field distributions, on whether they are monodomain or polydomain structures and on linear or nonlinear light absorptive processes. In each case, we derive the general weak response where bend in each direction is treated independently of that in others. In a subsequent paper, we address the reverse phenomenon, that is of strong spontaneous distortion leading to curvature suppression.
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Affiliation(s)
- M. Warner
- Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - C. D. Modes
- Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - D. Corbett
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
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Sawa Y, Urayama K, Takigawa T, DeSimone A, Teresi L. Thermally Driven Giant Bending of Liquid Crystal Elastomer Films with Hybrid Alignment. Macromolecules 2010. [DOI: 10.1021/ma1003979] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yoshiki Sawa
- Department of Materials Chemistry, Kyoto University, Kyoto 615-8510, Japan
| | - Kenji Urayama
- Department of Materials Chemistry, Kyoto University, Kyoto 615-8510, Japan
| | - Toshikazu Takigawa
- Department of Materials Chemistry, Kyoto University, Kyoto 615-8510, Japan
| | - Antonio DeSimone
- SISSA-International School for Advanced Studies, I-34151 Trieste, Italy
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Hrozhyk U, Serak S, Tabiryan N, White TJ, Bunning TJ. Bidirectional photoresponse of surface pretreated azobenzene liquid crystal polymer networks. OPTICS EXPRESS 2009; 17:716-722. [PMID: 19158885 DOI: 10.1364/oe.17.000716] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the photodriven, polarization-controlled response of UV-pretreated azobenzene-based liquid crystal polymer networks (azo- LCN) of polydomain orientation to higher wavelength CW argon-ion laser light (Ar(+)) of 457-514 nm. The significant absorbance of the azo-LCN cantilever in the UV is used to form an approximately 1 microm thick cis-isomer rich skin. Subsequent exposure to the Ar(+) laser drives a bidirectional bending process that is the result of two distinguishable photochemical processes. First, 457-514 nm laser light (regardless of polarization state) drives cis-trans photoisomerization of the UV-pretreated surface, restoring the order of the azobenzene liquid crystalline moieties. Mechanically, the cis-trans process results in an expansion on the exposed surface that forces the cantilever to undergo a rapid bend away from the laser source. Once a sufficient number of trans-azobenzene moieties are regenerated, continued Ar(+) illumination promotes both the trans-cis and cis-trans processes enabling trans-cis-trans reorientation. In this particular system and conditions, trans-cis-trans reorientation enables polarization controlled mechanical bending of different angles towards the Ar(+) source. Photomechanical responses of UV-pretreated azo-LCN demonstrate the viability of photogenerated effects in UV-rich environments such as space.
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Affiliation(s)
- Uladzimir Hrozhyk
- BEAM Engineering for Advanced Measurements Corporation, 809 South Orlando Ave., Suite I, Winter Park, Florida 32789, USA
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White TJ, Serak SV, Tabiryan NV, Vaia RA, Bunning TJ. Polarization-controlled, photodriven bending in monodomain liquid crystal elastomer cantilevers. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b818457g] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Corbett D, Warner M. Polarization dependence of optically driven polydomain elastomer mechanics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:061701. [PMID: 19256852 DOI: 10.1103/physreve.78.061701] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Indexed: 05/27/2023]
Abstract
We model how polarized and unpolarized light can cause mechanical response in polydomain nematic and related photoelastomers. The reduction of order by heating and the consequential large strains that are known from nematic elastomers can alternatively be caused by light-induced bending of rodlike dye molecules which then equally reduce the order of their nematic hosts. While there is no mechanical response to heating of polydomain elastomers, mechanical response to light is possible by the selective absorption of light according to how domains are aligned with respect to the polarization direction or with respect to the propagation direction in the case of unpolarized light. We find large contractions or elongations, depending on the nature of polarization. The responses are nonmonotonic with light intensity.
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Affiliation(s)
- D Corbett
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom
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