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Choi SH, Kim JH, Ahn J, Kim T, Jung Y, Won D, Bang J, Pyun KR, Jeong S, Kim H, Kim YG, Ko SH. Phase patterning of liquid crystal elastomers by laser-induced dynamic crosslinking. NATURE MATERIALS 2024; 23:834-843. [PMID: 38532072 DOI: 10.1038/s41563-024-01845-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/21/2024] [Indexed: 03/28/2024]
Abstract
Liquid crystal elastomers hold promise in various fields due to their reversible transition of mechanical and optical properties across distinct phases. However, the lack of local phase patterning techniques and irreversible phase programming has hindered their broad implementation. Here we introduce laser-induced dynamic crosslinking, which leverages the precision and control offered by laser technology to achieve high-resolution multilevel patterning and transmittance modulation. Incorporation of allyl sulfide groups enables adaptive liquid crystal elastomers that can be reconfigured into desired phases or complex patterns. Laser-induced dynamic crosslinking is compatible with existing processing methods and allows the generation of thermo- and strain-responsive patterns that include isotropic, polydomain and monodomain phases within a single liquid crystal elastomer film. We show temporary information encryption at body temperature, expanding the functionality of liquid crystal elastomer devices in wearable applications.
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Affiliation(s)
- Seok Hwan Choi
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Ju Hee Kim
- Department of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Jiyong Ahn
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Taegyeom Kim
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Yeongju Jung
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Daeyeon Won
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Junhyuk Bang
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Kyung Rok Pyun
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Seongmin Jeong
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Hyunsu Kim
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea
| | - Young Gyu Kim
- Department of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Seung Hwan Ko
- Department of Mechanical Engineering, Seoul National University, Seoul, Republic of Korea.
- Institute of Engineering Research / Institute of Advanced Machinery and Design (SNU-IAMD), Seoul National University, Seoul, Republic of Korea.
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, Korea.
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2
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Wang HQ, Tang Y, Huang ZY, Wang FZ, Qiu PF, Zhang X, Li CH, Li Q. A Dual-Responsive Liquid Crystal Elastomer for Multi-Level Encryption and Transient Information Display. Angew Chem Int Ed Engl 2023; 62:e202313728. [PMID: 37818673 DOI: 10.1002/anie.202313728] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 10/12/2023]
Abstract
Information security has gained increasing attention in the past decade, leading to the development of advanced materials for anti-counterfeiting, encryption and instantaneous information display. However, it remains challenging to achieve high information security with simple encryption procedures and low-energy stimuli. Herein, a series of strain/temperature-responsive liquid crystal elastomers (LCEs) are developed to achieve dual-modal, multi-level information encryption and real-time, rewritable transient information display. The as-prepared polydomain LCEs can change from an opaque state to a transparent state under strain or temperature stimuli, with the transition strains or temperatures highly dependent on the concentration of long-chain flexible spacers. Information encrypted by different LCE inks can be decrypted under specific strains or temperatures, leading to multi-level protection of information security. Furthermore, with the combination of the phase transition of polydomain LCEs and the photothermal effect of multi-walled carbon nanotubes (MWCNTs), we achieved a repeatable transient information display by using near-infrared (NIR) light as a pen for writing. This study provides new insight into the development of advanced encryption materials with versatility and high security for broad applications.
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Affiliation(s)
- Hong-Qin Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Yuqi Tang
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, 211189, Nanjing, China
| | - Zi-Yang Huang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Fang-Zhou Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Peng-Fei Qiu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Xinfang Zhang
- Materials Science Graduate Program, Kent State University, 44242, Kent, Ohio, USA
| | - Cheng-Hui Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Quan Li
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, 211189, Nanjing, China
- Materials Science Graduate Program, Kent State University, 44242, Kent, Ohio, USA
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3
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Yasuoka H, Takahashi KZ, Aoyagi T. Impact of molecular architectures on mesogen reorientation relaxation and post-relaxation stress of liquid crystal elastomers under electric fields. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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4
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Brighenti R, Cosma MP. Multiphysics modelling of light-actuated liquid crystal elastomers. Proc Math Phys Eng Sci 2023. [DOI: 10.1098/rspa.2022.0417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Liquid crystalline elastomers (LCEs) represent a promising class of responsive polymers whose physical properties are peculiar to both fluids and solids. Thanks to their microscale structure made of elongated rigid molecules (mesogens)—characterized by their capability to reversibly switch from an isotropic to an ordered state—LCEs exhibit a number of remarkable physical effects, such as self-deformation and mechanical actuation triggered by external stimuli. Efficient and physics-based modelling, aimed at designing and optimizing LCE-based devices (such as artificial muscles, deployable structures, soft actuators, etc.), is a fundamental tool to quantitatively describe their mechanical behaviour in real applications. In the present study, we illustrate the multi-physics modelling of light-driven deformation of LCEs, based on the photo-thermal energy conversion. The role played by the light diffusion and heat transfer within the medium is considered and their effect on the obtainable actuation is studied through numerical simulations based on the multi-physics theory developed.
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Affiliation(s)
- Roberto Brighenti
- Department of Engineering and Architecture, University of Parma, Viale delle Scienze 181/A, 43124 Parma, Italy
| | - Mattia P. Cosma
- Department of Engineering and Architecture, University of Parma, Viale delle Scienze 181/A, 43124 Parma, Italy
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5
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Regression analysis for predicting the elasticity of liquid crystal elastomers. Sci Rep 2022; 12:19788. [PMID: 36396780 PMCID: PMC9672114 DOI: 10.1038/s41598-022-23897-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022] Open
Abstract
It is highly desirable but difficult to understand how microscopic molecular details influence the macroscopic material properties, especially for soft materials with complex molecular architectures. In this study we focus on liquid crystal elastomers (LCEs) and aim at identifying the design variables of their molecular architectures that govern their macroscopic deformations. We apply the regression analysis using machine learning (ML) to a database containing the results of coarse grained molecular dynamics simulations of LCEs with various molecular architectures. The predictive performance of a surrogate model generated by the regression analysis is also tested. The database contains design variables for LCE molecular architectures, system and simulation conditions, and stress-strain curves for each LCE molecular system. Regression analysis is applied using the stress-strain curves as objective variables and the other factors as explanatory variables. The results reveal several descriptors governing the stress-strain curves. To test the predictive performance of the surrogate model, stress-strain curves are predicted for LCE molecular architectures that were not used in the ML scheme. The predicted curves capture the characteristics of the results obtained from molecular dynamics simulations. Therefore, the ML scheme has great potential to accelerate LCE material exploration by detecting the key design variables in the molecular architecture and predicting the LCE deformations.
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6
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Yasuoka H, Takahashi KZ, Aoyagi T. Trade-off effect between the stress and strain range in the soft elasticity of liquid crystalline elastomers. Polym J 2022. [DOI: 10.1038/s41428-022-00641-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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Molecular architecture dependence of mesogen rotation during uniaxial elongation of liquid crystal elastomers. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123970] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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8
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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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9
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Shen KH, Fan M, Hall LM. Molecular Dynamics Simulations of Ion-Containing Polymers Using Generic Coarse-Grained Models. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02557] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Kuan-Hsuan Shen
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Mengdi Fan
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Lisa M. Hall
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
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10
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Martin Linares CP, Traugutt NA, Saed MO, Martin Linares A, Yakacki CM, Nguyen TD. The effect of alignment on the rate-dependent behavior of a main-chain liquid crystal elastomer. SOFT MATTER 2020; 16:8782-8798. [PMID: 32812997 DOI: 10.1039/d0sm00125b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This study investigated the effect of alignment on the rate-dependent behavior of a main-chain liquid crystal elastomer (LCE). Polydomain nematic LCE networks were synthesized from a thiol-acrylate Michael addition reaction in the isotropic state. The polydomain networks were stretched to different strain levels to induce alignment then crosslinked in a second stage photopolymerization process. The LCE networks were subjected to dynamic mechanical tests to measure the temperature-dependent storage modulus and uniaxial tension load-unload tests to measure the rate-dependence of the Young's modulus, mechanical dissipation, and characteristics of the soft stress response. Three-dimensional (3D) digital image correlation (DIC) was used to characterize the effect of domain/mesogen relaxation on the strain fields. All LCE networks exhibited a highly rate-dependent stress response with significant inelastic strains after unloading. The Young's modulus of the loading curve and hysteresis of the load-unload curves showed a power-law dependence on the strain rate. The Young's modulus increased with alignment and larger anisotropy and a smaller power-law exponent was measured for the Young's modulus and hysteresis for the highly aligned monodomains. The polydomain and pre-stretched networks loaded perpendicular to the alignment direction exhibited a soft stress response that featured a rate-dependent peak stress, strain-softening, and strain-stiffening. The 3D-DIC strain fields for the polydomain network and programmed networks stretched in the perpendicular direction were highly heterogeneous, showing regions of alternating higher and lower strains. The strain variations increased initially with loading, peaked during the strain softening part of the stress response, then decreased during the strain stiffening part of the stress response. Greater variability was measured for lower strain rates. These observations suggest that local domain/mesogen relaxation led to the development of the heterogeneous strain patterns and strain softening in stress response. These findings improved understanding of the kinetics of mesogen relaxation and its contributions to the rate-dependent stress response and mechanical dissipation.
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Affiliation(s)
| | - Nicholas A Traugutt
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, USA
| | - Mohand O Saed
- Department of Physics, University of Cambridge, Cambridge, UK
| | | | - Christopher M Yakacki
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, USA
| | - Thao D Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, USA.
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11
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Doi H, Takahashi KZ, Tagashira K, Fukuda JI, Aoyagi T. Machine learning-aided analysis for complex local structure of liquid crystal polymers. Sci Rep 2019; 9:16370. [PMID: 31705002 PMCID: PMC6841663 DOI: 10.1038/s41598-019-51238-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/26/2019] [Indexed: 11/09/2022] Open
Abstract
Elucidation of mesoscopic structures of molecular systems is of considerable scientific and technological interest for the development and optimization of advanced materials. Molecular dynamics simulations are a promising means of revealing macroscopic physical properties of materials from a microscopic viewpoint, but analysis of the resulting complex mesoscopic structures from microscopic information is a non-trivial and challenging task. In this study, a Machine Learning-aided Local Structure Analyzer (ML-LSA) is developed to classify the complex local mesoscopic structures of molecules that have not only simple atomistic group units but also rigid anisotropic functional groups such as mesogens. The proposed ML-LSA is applied to classifying the local structures of liquid crystal polymer (LCP) systems, which are of considerable scientific and technological interest because of their potential for sensors and soft actuators. A machine learning (ML) model is constructed from small, and thus computationally less costly, monodomain LCP trajectories. The ML model can distinguish nematic- and smectic-like monodomain structures with high accuracy. The ML-LSA is applied to large, complex quenched LCP structures, and the complex local structures are successfully classified as either nematic- or smectic-like. Furthermore, the results of the ML-LSA suggest the best order parameter for distinguishing the two mesogenic structures. Our ML model enables automatic and systematic analysis of the mesogenic structures without prior knowledge, and thus can overcome the difficulty of manually determining the specific order parameter required for the classification of complex structures.
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Affiliation(s)
- Hideo Doi
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan
| | - Kazuaki Z Takahashi
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
| | - Kenji Tagashira
- Research Association of High-Throughput Design and Development for Advanced Functional Materials, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan
| | - Jun-Ichi Fukuda
- Department of Physics, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Fukuoka, 819-0395, Japan
| | - Takeshi Aoyagi
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan
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12
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Development of Coarse-Grained Liquid-Crystal Polymer Model with Efficient Electrostatic Interaction: Toward Molecular Dynamics Simulations of Electroactive Materials. MATERIALS 2018; 11:ma11010083. [PMID: 29316621 PMCID: PMC5793581 DOI: 10.3390/ma11010083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/30/2017] [Accepted: 01/03/2018] [Indexed: 02/03/2023]
Abstract
Liquid-crystal polymers (LCPs) are well known materials for functional sensor and actuators, because of their high-responsiveness to an electric field. Owing to their complex physical nature, however, the prediction of the functions of LCPs is a challenge. To attack this problem from a molecular point of view, a simulation study is a promising approach. In this work, for future applications of molecular dynamics simulations to problems involving an electric field, we develop an LCP model which consists of coarse-grained mesogenic molecules and smeared charges. For the smearing function of the electrostatic force, the Gauss error function is introduced. This smearing is optimized to attain a reasonable accuracy for phase transition phenomena of liquid crystal while numerical instabilities arising from the singularity of the Coulomb potential are circumvented. For swelling systems, our LCP model exhibits the characteristics of both liquid crystals and unentangled polymer chains; orientational order of the mesogenic units and Rouse-like relaxation dynamics. Our coarse-grained LCP model successfully incorporates electric charges and dipoles and is therefore applicable to problems concerning an electric field.
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13
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Kularatne RS, Kim H, Boothby JM, Ware TH. Liquid crystal elastomer actuators: Synthesis, alignment, and applications. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24287] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Ruvini S. Kularatne
- Department of Bioengineering; University of Texas at Dallas; 800 W. Campbell Rd. Richardson Texas 75080 USA
| | - Hyun Kim
- Department of Bioengineering; University of Texas at Dallas; 800 W. Campbell Rd. Richardson Texas 75080 USA
| | - Jennifer M. Boothby
- Department of Bioengineering; University of Texas at Dallas; 800 W. Campbell Rd. Richardson Texas 75080 USA
| | - Taylor H. Ware
- Department of Bioengineering; University of Texas at Dallas; 800 W. Campbell Rd. Richardson Texas 75080 USA
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14
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Azoug A, Vasconcellos V, Dooling J, Saed M, Yakacki C, Nguyen T. Viscoelasticity of the polydomain-monodomain transition in main-chain liquid crystal elastomers. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.06.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Agra-Kooijman DM, Fisch MR, Joshi L, Ren W, McMullan PJ, Griffin AC, Kumar S. Dual relaxation and structural changes under uniaxial strain in main-chain smectic-C liquid crystal elastomer. Phys Chem Chem Phys 2015; 17:191-9. [DOI: 10.1039/c4cp04713c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Relaxation rate of the chevron angle, α becomes about ten times faster at strains exceeding 0.7 than at low strains.
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Affiliation(s)
| | - Michael R. Fisch
- College of Applied Engineering Sustainability and Technology
- Kent State University
- Kent
- USA
| | - Leela Joshi
- Department of Physics
- Kent State University
- Kent
- USA
- Department of Physics
| | - Wanting Ren
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - Philip J. McMullan
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - Anselm C. Griffin
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
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16
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Skačej G, Zannoni C. Molecular Simulations Shed Light on Supersoft Elasticity in Polydomain Liquid Crystal Elastomers. Macromolecules 2014. [DOI: 10.1021/ma501836j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gregor Skačej
- Faculty
of Mathematics and Physics, University of Ljubljana, Jadranska
19, SI-1000 Ljubljana, Slovenia
- NAMASTE Centre
of Excellence, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Claudio Zannoni
- Dipartimento
di Chimica Industriale “Toso Montanari” and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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17
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18
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Liarte DB. Tricritical behavior of soft nematic elastomers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:062144. [PMID: 24483422 DOI: 10.1103/physreve.88.062144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 06/03/2023]
Abstract
We propose a lattice statistical model to investigate the phase diagrams and the soft responses of nematic liquid-crystal elastomers. Using suitably scaled infinite-range interactions, we obtain exact self-consistent equations for the tensor components of the nematic order parameter in terms of temperature, the distortion and stress tensors, and the initial nematic order. These equations are amenable to simple numerical calculations, which are used to characterize the low-temperature soft regime. We find a peculiar phase diagram, in terms of temperature and the diagonal component of the distortion tensor along the stretching direction, with first- and second-order transitions to the soft phase, and the prediction of tricritical points. This behavior is not qualitatively changed if we use different values of the initial nematic order parameter.
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Affiliation(s)
- Danilo B Liarte
- Laboratory of Atomic and Solid State Physics, Clark Hall, Cornell University, Ithaca, New York 14853-2501, USA and Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970, São Paulo, São Paulo, Brazil
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