1
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Skačej G, Querciagrossa L, Zannoni C. On the Effects of Different trans and cis Populations in Azobenzene Liquid Crystal Elastomers: A Monte Carlo Investigation. ACS APPLIED POLYMER MATERIALS 2023; 5:5805-5815. [PMID: 37588085 PMCID: PMC10426334 DOI: 10.1021/acsapm.3c00361] [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: 02/23/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
We investigate main-chain liquid crystal elastomers (LCEs) formed by photoresponsive azobenzene units with different populations of trans and cis conformers (from fully trans to fully cis). We study their macroscopic properties as well as their molecular organization using extensive Monte Carlo simulations of a simple coarse-grained model where the trans and cis conformers are represented by soft-core biaxial Gay-Berne particles with size and interaction energy parameters obtained by fitting a bare bone azobenzene moiety represented at atomistic level. We find that increasing the fraction of cis conformers, as could be obtained by near-UV irradiation, shifts the nematic-isotropic transition to a lower temperature, consistently with experiment, while generating internal stress in a clamped sample. An analysis of pair distributions shows that the immediate surroundings of a bent cis molecule are slightly less dense and more orientationally disordered in comparison with that of a trans conformer. Comparing nematic and smectic LCEs, actuation in the smectic phase proved less effective, disrupting the smectic layers to some extent but preserving orientational order of the azobenzene moieties.
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Affiliation(s)
- Gregor Skačej
- Faculty
of Mathematics and Physics, University of
Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Lara Querciagrossa
- Dipartimento
di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
- CINECA, Via Magnanelli 6/3, I-40033 Casalecchio di Reno, Italy
| | - Claudio Zannoni
- Dipartimento
di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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2
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Takahashi KZ. Molecular cluster analysis using local order parameters selected by machine learning. Phys Chem Chem Phys 2022; 25:658-672. [PMID: 36484716 DOI: 10.1039/d2cp03696g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Accurately extracting local molecular structures is essential for understanding the mechanisms of phase and structural transitions. A promising method to characterize the local molecular structure is defining the value of the local order parameter (LOP) for each particle. This work develops the Molecular Assembly structure Learning package for Identifying Order parameters (MALIO), a machine learning package that can propose an optimal (set of) LOP(s) quickly and automatically for a huge number of LOP species and various methods of selecting neighboring particles for the calculation. We applied this package to distinguish between the nematic and smectic phases of uniaxial liquid crystal molecules, and selected candidate LOPs that could be used to precisely observe the nematic-smectic phase transition. The LOP candidates were used to observe the nucleation and subsequent percolation transition, and the effect of the choice of LOP species and neighboring particles on the statistics of local molecular structures (clusters) was examined. The procedure revealed the time evolution of the number of clusters and the dependence of the percolation curve on the number of neighboring particles for each LOP species. The LOP species with the lowest dependence on the number of neighboring particles was the best-performing LOP species in the MALIO screening strategy. These results not only show that machine learning can powerfully screen a huge number of LOP species and suggest only a few promising candidates, but also indicate that MALIO can select the best LOP species.
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Affiliation(s)
- 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, 305-8568, Ibaraki, Japan.
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3
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Ahmadpour-Samani P, Zahedi P. An investigation on nematic-isotropic phase transition, viscosity and diffusion coefficient of liquid crystalline elastomers at different temperatures using molecular dynamics simulation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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4
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Xiao YY, Jiang ZC, Hou JB, Chen XS, Zhao Y. Electrically driven liquid crystal network actuators. SOFT MATTER 2022; 18:4850-4867. [PMID: 35730498 DOI: 10.1039/d2sm00544a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Soft actuators based on liquid crystal networks (LCNs) have aroused great scientific interest for use as stimuli-controlled shape-changing and moving components for robotic devices due to their fast, large, programmable and solvent-free actuation responses. Recently, various LCN actuators have been implemented in soft robotics using stimulus sources such as heat, light, humidity and chemical reactions. Among them, electrically driven LCN actuators allow easy modulation and programming of the input electrical signals (amplitude, phase, and frequency) as well as stimulation throughout the volume, rendering them promising actuators for practical applications. Herein, the progress of electrically driven LCN actuators regarding their construction, actuation mechanisms, actuation performance, actuation programmability and the design strategies for intelligent systems is elucidated. We also discuss new robotic functions and advanced actuation control. Finally, an outlook is provided, highlighting the research challenges faced with this type of actuator.
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Affiliation(s)
- Yao-Yu Xiao
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Zhi-Chao Jiang
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Jun-Bo Hou
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Xin-Shi Chen
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Yue Zhao
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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5
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Molecular Simulation Approaches to the Study of Thermotropic and Lyotropic Liquid Crystals. CRYSTALS 2022. [DOI: 10.3390/cryst12050685] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Over the last decade, the availability of computer time, together with new algorithms capable of exploiting parallel computer architectures, has opened up many possibilities in molecularly modelling liquid crystalline systems. This perspective article points to recent progress in modelling both thermotropic and lyotropic systems. For thermotropic nematics, the advent of improved molecular force fields can provide predictions for nematic clearing temperatures within a 10 K range. Such studies also provide valuable insights into the structure of more complex phases, where molecular organisation may be challenging to probe experimentally. Developments in coarse-grained models for thermotropics are discussed in the context of understanding the complex interplay of molecular packing, microphase separation and local interactions, and in developing methods for the calculation of material properties for thermotropics. We discuss progress towards the calculation of elastic constants, rotational viscosity coefficients, flexoelectric coefficients and helical twisting powers. The article also covers developments in modelling micelles, conventional lyotropic phases, lyotropic phase diagrams, and chromonic liquid crystals. For the latter, atomistic simulations have been particularly productive in clarifying the nature of the self-assembled aggregates in dilute solution. The development of effective coarse-grained models for chromonics is discussed in detail, including models that have demonstrated the formation of the chromonic N and M phases.
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6
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Wood EL, Greco C, Ivanov DA, Kremer K, Daoulas KC. Mesoscopic Modeling of a Highly-Ordered Sanidic Polymer Mesophase and Comparison With Experimental Data. J Phys Chem B 2022; 126:2285-2298. [PMID: 35290739 PMCID: PMC8958507 DOI: 10.1021/acs.jpcb.1c10599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Board-shaped polymers
form sanidic mesophases: assemblies of parallel
lamellae of stacked polymer backbones separated by disordered side
chains. Sanidics vary significantly with respect to polymer order
inside their lamellae, making them “stepping stones”
toward the crystalline state. Therefore, they are potentially interesting
for studying crystallization and technological applications. Building
on earlier mesoscopic models of the most disordered sanidics Σd, we focus on the other extreme, near-crystalline order, and
develop a generic model that captures a highly ordered Σr mesophase. Polymers are described by generic hindered-rotation
chains. Anisotropic nonbonded potentials, with strengths comparable
to the thermal energy, mimic board-like monomer shapes. Lamellae equilibrated
with Monte Carlo simulations, for a broad range of model parameters,
have intralamellar order typical for Σr mesophases:
periodically stacked polymers that are mutually registered along their
backbones. Our mesophase shows registration on both monomer and chain
levels. We calculate scattering patterns and compare with data published
for highly ordered sanidic mesophases of two different polymers: polyesters
and polypeptoids. Most of the generic structural features that were
identified in these experiments are present in our model. However,
our mesophase has correlations between chains located in different
lamellae and is therefore closer to the crystalline state than the
experimental samples.
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Affiliation(s)
- Emma L Wood
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Cristina Greco
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Dimitri A Ivanov
- Institute for Problems of Chemical Physics, Russian Academy of Sciences, Semenov Prospect 1, 142432 Chernogolovka, Russia.,Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia.,Institut de Sciences des Matériaux de Mulhouse, CNRS UMR 7361, 15 Jean Starcky, F-68057 Mulhouse, France.,Sirius University of Science and Technology, 1 Olympic Ave, 354340, Sochi, Russia
| | - Kurt Kremer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Kostas Ch Daoulas
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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7
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Mihai LA, Wang H, Guilleminot J, Goriely A. Nematic liquid crystalline elastomers are aeolotropic materials. Proc Math Phys Eng Sci 2021; 477:20210259. [PMID: 35153581 PMCID: PMC8424302 DOI: 10.1098/rspa.2021.0259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/04/2021] [Indexed: 11/12/2022] Open
Abstract
Continuum models describing ideal nematic solids are widely used in theoretical studies of liquid crystal elastomers. However, experiments on nematic elastomers show a type of anisotropic response that is not predicted by the ideal models. Therefore, their description requires an additional term coupling elastic and nematic responses, to account for aeolotropic effects. In order to better understand the observed elastic response of liquid crystal elastomers, we analyse theoretically and computationally different stretch and shear deformations. We then compare the elastic moduli in the infinitesimal elastic strain limit obtained from the molecular dynamics simulations with the ones derived theoretically, and show that they are better explained by including nematic order effects within the continuum framework.
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Affiliation(s)
- L Angela Mihai
- School of Mathematics, Cardiff University, Senghennydd Road, Cardiff CF24 4AG, UK
| | - Haoran Wang
- Department of Mechanical and Aerospace Engineering,Utah State University, Logan, UT 84322-4130, USA
| | - Johann Guilleminot
- Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford OX2 6GG, UK
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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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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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11
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Orlandi S, Zannoni C. Molecular organizations of conical mesogenic fullerenes. SOFT MATTER 2018; 14:3882-3888. [PMID: 29726555 DOI: 10.1039/c7sm02459b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have studied liquid crystal phases formed by fullerenes functionalized with mesogenic groups yielding a cone-shaped molecular structure. We have modelled these shuttlecock-like molecules with a set of Gay-Berne particles grafted with flexible springs to a spherical core and we have studied, using Monte Carlo simulations, their phase organization, also with a view to examining their possible use as candidate organic photovoltaic materials. We have found that, upon cooling from the isotropic phase, the system forms a columnar phase, like in the experimental work of Kato and coworkers [T. Kato et al., Nature, 2002, 419, 702]. However the phase is made of polar stacks extending not more than about ten molecules, which could limit their usefulness in enhancing and directing charge transport for possible photovoltaic applications.
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Affiliation(s)
- Silvia Orlandi
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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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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Chung H, Choi J, Yun JH, Cho M. Nonlinear photomechanics of nematic networks: upscaling microscopic behaviour to macroscopic deformation. Sci Rep 2016; 6:20026. [PMID: 26828417 PMCID: PMC4734330 DOI: 10.1038/srep20026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 12/08/2015] [Indexed: 11/29/2022] Open
Abstract
A liquid crystal network whose chromophores are functionalized by photochromic dye exhibits light-induced mechanical behaviour. As a result, the micro-scaled thermotropic traits of the network and the macroscopic phase behaviour are both influenced as light alternates the shape of the dyes. In this paper, we present an analysis of this photomechanical behaviour based on the proposed multiscale framework, which incorporates the molecular details of microstate evolution into a continuum-based understanding. The effects of trans-to-cis photoisomerization driven by actinic light irradiation are first examined using molecular dynamics simulations, and are compared against the predictions of the classical dilution model; this reveals certain characteristics of mesogenic interaction upon isomerization, followed by changes in the polymeric structure. We then upscale the thermotropic phase-related information with the aid of a nonlinear finite element analysis; macroscopic deflection with respect to the wide ranges of temperature and actinic light intensity are thereby examined, which reveals that the classical model underestimates the true deformation. This work therefore provides measures for analysing photomechanics in general by bridging the gap between the micro- and macro-scales.
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Affiliation(s)
- Hayoung Chung
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-744, South Korea
| | - Joonmyung Choi
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-744, South Korea
| | - Jung-Hoon Yun
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-744, South Korea
| | - Maenghyo Cho
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-744, South Korea
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14
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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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15
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Fuchigami Y, Takigawa T, Urayama K. Electrical Actuation of Cholesteric Liquid Crystal Gels. ACS Macro Lett 2014; 3:813-818. [PMID: 35590706 DOI: 10.1021/mz5003382] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate that the cholesteric liquid crystal (CLC) gels with a global helical variation in their orientation exhibit the pronounced electro-optical and electromechanical effects under an unconstrained geometry. A sufficiently high electric field imposed along the helical axis drives a finite elongation exceeding 30% along the field axis, as well as a finite redshift of the selective reflection band which is opposite to the blueshift often observed for the conventional CLCs and the in situ polymer stabilized CLCs under an electric field.
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Affiliation(s)
- Yuuta Fuchigami
- Department
of Material Chemistry, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Toshikazu Takigawa
- Department
of Material Chemistry, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kenji Urayama
- Department
of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, 606-8585 Japan
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16
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Whitmer JK, Roberts TF, Shekhar R, Abbott NL, de Pablo JJ. Modeling the polydomain-monodomain transition of liquid crystal elastomers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:020502. [PMID: 23496448 PMCID: PMC4434589 DOI: 10.1103/physreve.87.020502] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/10/2012] [Indexed: 06/01/2023]
Abstract
We study the mechanism of the polydomain-monodomain transition in liquid crystalline elastomers at the molecular scale. A coarse-grained model is proposed in which mesogens are described as ellipsoidal particles. Molecular dynamics simulations are used to examine the transition from a polydomain state to a monodomain state in the presence of uniaxial strain. Our model demonstrates soft elasticity, similar to that exhibited by side-chain elastomers in the literature. By analyzing the growth dynamics of nematic domains during uniaxial extension, we provide direct evidence that at a molecular level the polydomain-monodomain transition proceeds through cluster rotation and domain growth.
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Affiliation(s)
- Jonathan K. Whitmer
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison WI 53706-1691
| | - Tyler F. Roberts
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison WI 53706-1691
| | - Raj Shekhar
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison WI 53706-1691
| | - Nicholas L. Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison WI 53706-1691
| | - Juan J. de Pablo
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637
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17
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Muccioli L, D’Avino G, Berardi R, Orlandi S, Pizzirusso A, Ricci M, Roscioni OM, Zannoni C. Supramolecular Organization of Functional Organic Materials in the Bulk and at Organic/Organic Interfaces: A Modeling and Computer Simulation Approach. Top Curr Chem (Cham) 2013; 352:39-101. [DOI: 10.1007/128_2013_470] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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