1
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Jin B, Zhu Z, Wong TW, Chen G. Network Topology Optimization for Alignment Programming of a Dynamic Liquid Crystalline Organo-Gel. ACS Macro Lett 2023; 12:1486-1490. [PMID: 37874195 DOI: 10.1021/acsmacrolett.3c00512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Liquid crystalline elastomers (LCEs) exhibit muscle-like actuation upon an external stimulus. To control this, various alignment programming strategies have been developed over the past decades. Among them, force-directed solvent evaporation, namely, that the alignment depends on the applied external force during solvent evaporation, is appreciated for its universality in material design and versatility in attainable actuations. Here, we investigate the influence of network topology on the alignment programming of a liquid crystalline (LC) organo-gel via varying feeding ratios of the monomers. As a result, distinct self-supporting actuations can be repeatedly introduced into a topology-optimized LC organo-gel. Beyond this, the bond exchange reaction of the embedded ester groups can be activated upon heating, which enables alignment manipulation based on dynamic network reconfiguration after drying. The availability of inviting two distinct programming strategies into one LCE network allows us to regulate the LCE alignment at both the gel and dried states, offering ample room to diversify actuation manners. Our design principle shall be adopted by other dynamic LCE systems owing to its maneuverability.
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Affiliation(s)
- Binjie Jin
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Zhan Zhu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Tuck-Whye Wong
- Membrane Technology Research Centre, School of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia
| | - Guancong Chen
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, Zhejiang, China
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2
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Knapik-Kowalczuk J, Kramarczyk D, Jachowicz R, Paluch M. Effect of Shear Strain on the Supercooled Itraconazole. J Pharm Sci 2023; 112:1644-1652. [PMID: 36709801 DOI: 10.1016/j.xphs.2023.01.020] [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: 08/13/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023]
Abstract
This article investigated the effect of shear strain on the nematic itraconazole (ITR) from both elastic and plastic deformation regions. The rheo-dielectric technique was used for this purpose. It has been demonstrated that shear strain can change the sample color, liquid crystal alignment as well as its dielectric and thermal properties. The observed modifications depend on the shear strain value. One can distinguish four regions regarding the slope of ITR stress-strain dependence and caused changes. Proper alignment changes (obtained after the shearing procedure) can additionally affect the further recrystallization of ITR to other than the initial, i.e., second polymorphic form.
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Affiliation(s)
- Justyna Knapik-Kowalczuk
- Faculty of Science and Technology, Institute of Physics, University of Silesia in Katowice, SMCEBI, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland.
| | - Daniel Kramarczyk
- Faculty of Science and Technology, Institute of Physics, University of Silesia in Katowice, SMCEBI, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
| | - Renata Jachowicz
- Faculty of Pharmacy, Department of Pharmaceutical Technology and Biopharmaceutics, Jagiellonian University, Medyczna 9, 30-688 Kraków, Poland
| | - Marian Paluch
- Faculty of Science and Technology, Institute of Physics, University of Silesia in Katowice, SMCEBI, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
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3
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Bauman GE, Hoang JD, Toney MF, White TJ. Degree of Orientation in Liquid Crystalline Elastomers Defines the Magnitude and Rate of Actuation. ACS Macro Lett 2023; 12:248-254. [PMID: 36715430 DOI: 10.1021/acsmacrolett.2c00754] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The anisotropy of liquid crystalline elastomers (LCEs) is derived from the interaction-facilitated orientation of the molecular constituents. Here, we correlate the thermomechanical response of a series of LCEs subjected to mechanical alignment to measurements of the Hermans orientation parameter. The LCEs were systematically prepared with varying concentrations of liquid crystalline mesogens, which affects the relative degree of achievable order. These compositions were subject to varying degrees of mechanical alignment to prepare LCEs with orientations that span a wide range of orientation parameters. The stimuli-response of the LCEs indicates that the liquid crystalline content defines the temperature of actuation, whereas the orientation parameter of the LCE is intricately correlated to both the total actuation strain of the LCE as well as the rate of thermomechanical response.
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Affiliation(s)
- Grant E Bauman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States
| | - Jonathan D Hoang
- Materials Science and Engineering Program, University of Colorado Boulder, 613 UCB, Boulder, Colorado 80303, United States
| | - Michael F Toney
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States.,Materials Science and Engineering Program, University of Colorado Boulder, 613 UCB, Boulder, Colorado 80303, United States.,Renewable and Sustainable Energy Institute, University of Colorado Boulder, 027 UCB, Boulder, Colorado 80309, United States
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States.,Materials Science and Engineering Program, University of Colorado Boulder, 613 UCB, Boulder, Colorado 80303, United States
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4
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Bobnar M, Derets N, Umerova S, Domenici V, Novak N, Lavrič M, Cordoyiannis G, Zalar B, Rešetič A. Polymer-dispersed liquid crystal elastomers as moldable shape-programmable material. Nat Commun 2023; 14:764. [PMID: 36765062 PMCID: PMC9918464 DOI: 10.1038/s41467-023-36426-y] [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: 11/07/2022] [Accepted: 02/01/2023] [Indexed: 02/12/2023] Open
Abstract
The current development of soft shape-memory materials often results in materials that are typically limited to the synthesis of thin-walled specimens and usually rely on complex, low-yield manufacturing techniques to fabricate macro-sized, solid three-dimensional objects. However, such geometrical limitations and slow production rates can significantly hinder their practical implementation. In this work, we demonstrate a shape-memory composite material that can be effortlessly molded into arbitrary shapes or sizes. The composite material is made from main-chain liquid crystal elastomer (MC-LCE) microparticles dispersed in a silicone polymer matrix. Shape-programmability is achieved via low-temperature induced glassiness and hardening of MC-LCE inclusions, which effectively freezes-in any mechanically instilled deformations. Once thermally reset, the composite returns to its initial shape and can be shape-programmed again. Magnetically aligning MC-LCE microparticles prior to curing allows the shape-programmed artefacts to be additionally thermomechanically functionalized. Therefore, our material enables efficient morphing among the virgin, thermally-programmed, and thermomechanically-controlled shapes.
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Affiliation(s)
- Matej Bobnar
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Nikita Derets
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia ,grid.423485.c0000 0004 0548 8017On leave from: Ioffe Institute, Division of Physics of Dielectrics and Semiconductors, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - Saide Umerova
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Valentina Domenici
- grid.5395.a0000 0004 1757 3729Dipartimento di Chimica e Chimica Industriale, Università degli studi di Pisa, via Moruzzi 13, 56124 Pisa, Italy
| | - Nikola Novak
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Marta Lavrič
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - George Cordoyiannis
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Boštjan Zalar
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000 Ljubljana, Slovenia ,grid.445211.7Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Andraž Rešetič
- Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000, Ljubljana, Slovenia.
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5
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Cang Y, Liu J, Ryu M, Graczykowski B, Morikawa J, Yang S, Fytas G. On the origin of elasticity and heat conduction anisotropy of liquid crystal elastomers at gigahertz frequencies. Nat Commun 2022; 13:5248. [PMID: 36068238 PMCID: PMC9448779 DOI: 10.1038/s41467-022-32865-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 08/18/2022] [Indexed: 11/09/2022] Open
Abstract
Liquid crystal elastomers that offer exceptional load-deformation response at low frequencies often require consideration of the mechanical anisotropy only along the two symmetry directions. However, emerging applications operating at high frequencies require all five true elastic constants. Here, we utilize Brillouin light spectroscopy to obtain the engineering moduli and probe the strain dependence of the elasticity anisotropy at gigahertz frequencies. The Young's modulus anisotropy, E||/E⊥~2.6, is unexpectedly lower than that measured by tensile testing, suggesting disparity between the local mesogenic orientation and the larger scale orientation of the network strands. Unprecedented is the robustness of E||/E⊥ to uniaxial load that it does not comply with continuously transformable director orientation observed in the tensile testing. Likewise, the heat conductivity is directional, κ||/κ⊥~3.0 with κ⊥ = 0.16 Wm-1K-1. Conceptually, this work reveals the different length scales involved in the thermoelastic anisotropy and provides insights for programming liquid crystal elastomers on-demand for high-frequency applications.
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Affiliation(s)
- Yu Cang
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Zhangwu Road 100, Shanghai, 200092, China.,Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Jiaqi Liu
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA, 19104, USA
| | - Meguya Ryu
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.,National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8563, Japan
| | - Bartlomiej Graczykowski
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany.,Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, Poznan, 61-614, Poland
| | - Junko Morikawa
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Shu Yang
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA, 19104, USA.
| | - George Fytas
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany.
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6
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Javed M, Corazao T, Saed MO, Ambulo CP, Li Y, Kessler MR, Ware TH. Programmable Shape Change in Semicrystalline Liquid Crystal Elastomers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:35087-35096. [PMID: 35866446 DOI: 10.1021/acsami.2c07533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Liquid crystal elastomers (LCEs) are stimuli-responsive materials capable of reversible and programmable shape change in response to an environmental stimulus. Despite the highly responsive nature of these materials, the modest elastic modulus and blocking stress exhibited by these actuating materials can be limiting in some engineering applications. Here, we engineer a semicrystalline LCE, where the incorporation of semicrystallinity in a lightly cross-linked liquid crystalline network yields tough and highly responsive materials. Directed self-assembly can be employed to program director profiles through the thickness of the semicrystalline LCE. In short, we use the alignment of a liquid crystal monomer phase to pattern the anisotropy of a semicrystalline polymer network. Both the semicrystalline-liquid crystalline and liquid crystalline-isotropic phase transition temperatures provide controllable shape transformations. A planarly aligned sample's normalized dimension parallel to the nematic director decreases from 1 at room temperature to 0.42 at 250 °C. The introduction of the semicrystalline nature also enhances the mechanical properties exhibited by the semicrystalline LCE. Semicrystalline LCEs have a storage modulus of 390 MPa at room temperature, and monodomain samples are capable of generating a contractile stress of 2.7 MPa on heating from 25 to 50 °C, far below the nematic to isotropic transition temperature. The robust mechanical properties of this material combined with the high actuation strain can be leveraged for applications such as soft robotics and actuators capable of doing significant work.
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Affiliation(s)
- Mahjabeen Javed
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Tyler Corazao
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
| | | | - Cedric P Ambulo
- Air Force Research Laboratory, Dayton, Ohio 45433, United States
| | - Yuzhan Li
- University of Science and Technology Beijing, Beijing 100083, China
| | - Michael R Kessler
- North Dakota State University, Fargo, North Dakota 58108, United States
| | - Taylor H Ware
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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7
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Barnes M, Cetinkaya S, Ajnsztajn A, Verduzco R. Understanding the effect of liquid crystal content on the phase behavior and mechanical properties of liquid crystal elastomers. SOFT MATTER 2022; 18:5074-5081. [PMID: 35764591 DOI: 10.1039/d2sm00480a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Liquid crystal elastomers are stimuli-responsive, shape-shifting materials. They typically require high temperatures for actuation which prohibits their use in many applications, such as biomedical devices. In this work, we demonstrate a simple and general approach to tune the order-to-disorder transition temperature (TODT) or nematic-to-isotropic transition temperature (TNI) of LCEs through variation of the overall liquid crystal mass content. We demonstrate reduction of the TNI in nematic LCEs through the incorporation of non-mesogenic linkers or the addition of lithium salts, and show that the TNI varies linearly with liquid crystal mass content over a broad range, approximately 50 °C. We also analyze data from prior reports that include three different mesogens, different network linking chemistries, and different alignment strategies, and show that the linear trend in TODT with liquid crystal mass content also holds for these systems. Finally, we demonstrate a simple approach to quantifying the maximum actuation strain through measurement of the soft elastic plateau and demonstrate applications of nematic LCEs with low TODTs, including the first body-responsive LCE that curls around a human finger due to body heat, and a fluidic channel that directionally pumps liquid when heated.
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Affiliation(s)
- Morgan Barnes
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA.
| | - Sueda Cetinkaya
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, 77005, USA
| | - Alec Ajnsztajn
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA.
| | - Rafael Verduzco
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA.
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, 77005, USA
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8
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Beating of a Spherical Liquid Crystal Elastomer Balloon under Periodic Illumination. MICROMACHINES 2022; 13:mi13050769. [PMID: 35630236 PMCID: PMC9146708 DOI: 10.3390/mi13050769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022]
Abstract
Periodic excitation is a relatively simple and common active control mode. Owing to the advantages of direct access to environmental energy and controllability under periodic illumination, it enjoys broad prospects for application in soft robotics and opto-mechanical energy conversion systems. More new oscillating systems need to be excavated to meet the various application requirements. A spherical liquid crystal elastomer (LCE) balloon model driven by periodic illumination is proposed and its periodic beating is studied theoretically. Based on the existing dynamic LCE model and the ideal gas model, the governing equation of motion for the LCE balloon is established. The numerical calculations show that periodic illumination can cause periodic beating of the LCE balloon, and the beating period of the LCE balloon depends on the illumination period. For the maximum steady-state amplitude of the beating, there exists an optimum illumination period and illumination time rate. The optimal illumination period is proved to be equivalent to the natural period of balloon oscillation. The effect of system parameters on beating amplitude are also studied. The amplitude is mainly affected by light intensity, contraction coefficient, amount of gaseous substance, volume of LCE balloon, mass density, external pressure, and damping coefficient, but not the initial velocity. It is expected that the beating LCE balloon will be suitable for the design of light-powered machines including engines, prosthetic blood pumps, aircraft, and swimmers.
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9
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A Light-Powered Liquid Crystal Elastomer Spring Oscillator with Self-Shading Coatings. Polymers (Basel) 2022; 14:polym14081525. [PMID: 35458275 PMCID: PMC9028186 DOI: 10.3390/polym14081525] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/01/2022] [Accepted: 04/04/2022] [Indexed: 02/04/2023] Open
Abstract
The self-oscillating systems based on stimuli-responsive materials, without complex controllers and additional batteries, have great application prospects in the fields of intelligent machines, soft robotics, and light-powered motors. Recently, the periodic oscillation of an LCE fiber with a mass block under periodic illumination was reported. This system requires periodic illumination, which limits the application of self-sustained systems. In this paper, we creatively proposed a light-powered liquid crystal elastomer (LCE) spring oscillator with self-shading coatings, which can self-oscillate continuously under steady illumination. On the basis of the well-established dynamic LCE model, the governing equation of the LCE spring oscillator is formulated, and the self-excited oscillation is studied theoretically. The numerical calculations show that the LCE spring oscillator has two motion modes, static mode and oscillation mode, and the self-oscillation arises from the coupling between the light-driven deformation and its movement. Furthermore, the contraction coefficient, damping coefficient, painting stretch, light intensity, spring constant, and gravitational acceleration all affect the self-excited oscillation of the spring oscillator, and each parameter is a critical value for triggering self-excited oscillation. This work will provide effective help in designing new optically responsive structures for engineering applications.
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10
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Self-Sustained Collective Motion of Two Joint Liquid Crystal Elastomer Spring Oscillator Powered by Steady Illumination. MICROMACHINES 2022; 13:mi13020271. [PMID: 35208395 PMCID: PMC8876739 DOI: 10.3390/mi13020271] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 02/01/2023]
Abstract
For complex micro-active machines or micro-robotics, it is crucial to clarify the coupling and collective motion of their multiple self-oscillators. In this article, we construct two joint liquid crystal elastomer (LCE) spring oscillators connected by a spring and theoretically investigate their collective motion based on a well-established dynamic LCE model. The numerical calculations show that the coupled system has three steady synchronization modes: in-phase mode, anti-phase mode, and non-phase-locked mode, and the in-phase mode is more easily achieved than the anti-phase mode and the non-phase-locked mode. Meanwhile, the self-excited oscillation mechanism is elucidated by the competition between network that is achieved by the driving force and the damping dissipation. Furthermore, the phase diagram of three steady synchronization modes under different coupling stiffness and different initial states is given. The effects of several key physical quantities on the amplitude and frequency of the three synchronization modes are studied in detail, and the equivalent systems of in-phase mode and anti-phase mode are proposed. The study of the coupled LCE spring oscillators will deepen people’s understanding of collective motion and has potential applications in the fields of micro-active machines and micro-robots with multiple coupled self-oscillators.
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11
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Li Y, Keum JK, Wang J, Jiang N, Bras W, Kessler MR, Rios O. Multiscale Structural Characterization of a Smectic Liquid Crystalline Elastomer upon Mechanical Deformation Using Neutron Scattering. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yuzhan Li
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jong K. Keum
- Center for Nanophase Materials Sciences and Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jun Wang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Naisheng Jiang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wim Bras
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael R. Kessler
- Department of Mechanical Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Orlando Rios
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, United States
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12
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Barnes M, Sajadi SM, Parekh S, Rahman MM, Ajayan PM, Verduzco R. Reactive 3D Printing of Shape-Programmable Liquid Crystal Elastomer Actuators. ACS APPLIED MATERIALS & INTERFACES 2020; 12:28692-28699. [PMID: 32484325 DOI: 10.1021/acsami.0c07331] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
3D printed, stimuli-responsive materials that reversibly actuate between programmed shapes are promising for applications ranging from biomedical implants to soft robotics. However, current 3D printing of reversible actuators significantly limits the range of possible shapes and/or shape responses because they couple the print path to mathematically determined director profiles to elicit a desired shape change. Here, we report a reactive 3D-printing method that decouples printing and shape-programming steps, enabling a broad range of complex architectures and virtually any arbitrary shape changes. This method involves first printing liquid crystal elastomer (LCE) precursor solution into a catalyst bath, producing complex architectures defined by printing. Shape changes are then programmed through mechanical deformation and UV irradiation. Upon heating and cooling, the LCE reversibly shape-shifts between printed and programmed shapes, respectively. The potential of this method was demonstrated by programming a variety of arbitrary shape changes in a single printed material, producing auxetic LCE structures and symmetry-breaking shape changes in LCE sheets.
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Affiliation(s)
- Morgan Barnes
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Seyed M Sajadi
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Shaan Parekh
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Muhammad M Rahman
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Rafael Verduzco
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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13
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Li Y, Zhang Y, Goswami M, Vincent D, Wang L, Liu T, Li K, Keum JK, Gao Z, Ozcan S, Gluesenkamp KR, Rios O, Kessler MR. Liquid crystalline networks based on photo-initiated thiol-ene click chemistry. SOFT MATTER 2020; 16:1760-1770. [PMID: 31859322 DOI: 10.1039/c9sm01818b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Photo-initiated thiol-ene click chemistry is used to develop shape memory liquid crystalline networks (LCNs). A biphenyl-based di-vinyl monomer is synthesized and cured with a di-thiol chain extender and a tetra-thiol crosslinker using UV light. The effects of photo-initiator concentration and UV light intensity on the curing behavior and liquid crystalline (LC) properties of the LCNs are investigated. The chemical composition is found to significantly influence the microstructure and the related thermomechanical properties of the LCNs. The structure-property relationship is further explored using molecular dynamics simulations, revealing that the introduction of the chain extender promotes the formation of an ordered smectic LC phase instead of agglomerated structures. The concentration of the chain extender affects the liquid crystallinity of the LCNs, resulting in distinct thermomechanical and shape memory properties. This class of LCNs exhibits fast curing rates, high conversion levels, and tailorable liquid crystallinity, making it a promising material system for advanced manufacturing, where complex and highly ordered structures can be produced with fast reaction kinetics and low energy consumption.
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Affiliation(s)
- Yuzhan Li
- Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA.
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14
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Brannum MT, Auguste AD, Donovan BR, Godman NP, Matavulj VM, Steele AM, Korley LTJ, Wnek GE, White TJ. Deformation and Elastic Recovery of Acrylate-Based Liquid Crystalline Elastomers. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Michelle T. Brannum
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Anesia D. Auguste
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Brian R. Donovan
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Nicholas P. Godman
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Valentina M. Matavulj
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- Azimuth Corporation, Beavercreek, Ohio 45431, United States
| | - Aubrey M. Steele
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- Azimuth Corporation, Beavercreek, Ohio 45431, United States
| | - LaShanda T. J. Korley
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
- Department of Materials Science and Engineering and Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Gary E. Wnek
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Timothy J. White
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States
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15
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Mechanical energy dissipation in polydomain nematic liquid crystal elastomers in response to oscillating loading. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.01.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Wang Y, Burke KA. Phase behavior of main-chain liquid crystalline polymer networks synthesized by alkyne-azide cycloaddition chemistry. SOFT MATTER 2018; 14:9885-9900. [PMID: 30511082 DOI: 10.1039/c8sm01913d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Liquid crystalline polymer networks (LCNs) couple polymer chain organization to molecular ordering, the switching of which has been shown to impart stimuli-responsive properties, including actuation and one-way shape memory, to the networks. While LCNs have long been proposed as artificial muscles, recent reports have also suggested potential as dynamic biomaterial substrates. In contrast to many existing LCNs synthesized using hydrophobic spacers, this work investigates networks synthesized using more hydrophilic spacers to promote interaction with water. A challenge with such materials is liquid crystalline phases could be disrupted in hydrated networks. This work thus investigates the impact of polyether spacers and mesogen composition on the phase behavior of LCNs. Main-chain LCNs were synthesized using alkyne-azide cycloaddition ("click" chemistry), where two different mesogens (5yH and 5yMe) and a non-LC monomer (5yTe) were coupled with one of two different polyether spacers, poly(ethylene glycol) and poly(propylene glycol), and a crosslinker. The chemistry led to high gel fraction materials, the workup of which resulted in networks that displayed no difference in cellular toxicity due to leachable components compared to tissue culture plastic control. Calorimetric analysis, dynamic mechanical analysis, and X-ray scattering revealed the LC microstructure and temperature-responsive properties of the networks. The use of low molecular weight polyether spacers was found to prevent their crystallization within the LC network, and adjusting mesogen composition to enhance its LC phase stability allowed the use of spacers with larger molecular weights and pendant groups. Hydrated networks were found to rearrange their structure compared to dry networks, while maintaining their LC phases. Like other crosslinked LC materials, the networks display shape changes (actuation) that are tied to changes in LC ordering. The result is a new synthetic approach for polydomain networks that form stable LC phases that are tailorable using polyether spacers and may enable future application as hydrated, stimuli-responsive materials.
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Affiliation(s)
- Yongjian Wang
- Chemical and Biomolecular Engineering, University of Connecticut, 191 Auditorium Road Unit 3222, Storrs, CT 06269-3222, USA.
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17
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Rogez D, Krause S, Martinoty P. Main-chain liquid-crystal elastomers versus side-chain liquid-crystal elastomers: similarities and differences in their mechanical properties. SOFT MATTER 2018; 14:6449-6462. [PMID: 30035290 DOI: 10.1039/c8sm00936h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
After a general introduction on the main aspects of the mechanical properties of main-chain liquid-crystal elastomers (MCLCEs) and side-chain liquid-crystal elastomers (SCLCEs), new results will be presented dealing with several MCLCEs with a cross-linker density C = 8%, 6% and 4% and with a SCLCE with C = 10%, all prepared by the two-step cross-linking process. A non-SCLCE with bulky side-groups similar in shape to the mesogens was also synthesized for comparison with the SCLCE. Most of the experiments were performed with a piezorheometer allowing the determination of the shear anisotropy of the samples by applying shear in a direction parallel or perpendicular to the director, and with a thermo-elastic device for the E measurements. The main results concern: (a) the influence of the supercritical nature of SCLCE and the subcritical nature of MCLCEs on the mechanical properties of these elastomers, as well as that of SmC domains present in MCLCEs; (b) the relationship between the degrees of elongation and of anisotropy deduced from the variations of and during the poly-domain to mono-domain transition of the 10% SCLCE and the 8% MCLCE; (c) the determination of the Poisson's ratio showing that it is isotropic for the non-SCLCE, with a crossover between 0.5 (classical value for rubbers) for small strains and 0.38 for high strains, and anisotropic for the 10% SCLCE and 8% MCLCE, with values <0.5. The particular behaviors of the Poisson's ratios can be explained by confinement effects occurring when stretching increases.
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Affiliation(s)
- D Rogez
- Institut Charles Sadron, UPR 22, CNRS, 23 rue du Loess, 67034 Strasbourg Cedex 2, France.
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18
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Auguste AD, Ward JW, Hardin JO, Kowalski BA, Guin TC, Berrigan JD, White TJ. Enabling and Localizing Omnidirectional Nonlinear Deformation in Liquid Crystalline Elastomers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802438. [PMID: 30009428 DOI: 10.1002/adma.201802438] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/23/2018] [Indexed: 05/23/2023]
Abstract
Liquid crystalline elastomers (LCEs) are widely recognized for their exceptional promise as actuating materials. Here, the comparatively less celebrated but also compelling nonlinear response of these materials to mechanical load is examined. Prior examinations of planarly aligned LCEs exhibit unidirectional nonlinear deformation to mechanical loads. A methodology is presented to realize surface-templated homeotropic orientation in LCEs and omnidirectional nonlinearity in mechanical deformation. Inkjet printing of the homeotropic alignment surface localizes regions of homeotropic and planar orientation within a monolithic LCE element. The local control of the self-assembly and orientation of the LCE, when subject to rational design, yield functional materials continuous in composition with discontinuous mechanical deformation. The variation in mechanical deformation in the film can enable the realization of nontrivial performance. For example, a patterned LCE is prepared and shown to exhibit a near-zero Poisson's ratio. Further, it is demonstrated that the local control of deformation can enable the fabrication of rugged, flexible electronic devices. An additively manufactured device withstands complex mechanical deformations that would normally cause catastrophic failure.
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Affiliation(s)
- Anesia D Auguste
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
| | - Jeremy W Ward
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
| | - James O Hardin
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- UES Inc., 401 Dayton Xenia Rd, Beavercreek, OH, 45432, USA
| | - Benjamin A Kowalski
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- Azimuth Corporation, Beavercreek, OH, 45431, USA
| | - Tyler C Guin
- Azimuth Corporation, Beavercreek, OH, 45431, USA
| | - J Daniel Berrigan
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
| | - Timothy J White
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
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19
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Merkel DR, Traugutt NA, Visvanathan R, Yakacki CM, Frick CP. Thermomechanical properties of monodomain nematic main-chain liquid crystal elastomers. SOFT MATTER 2018; 14:6024-6036. [PMID: 29974115 DOI: 10.1039/c8sm01178h] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two-stage thiol-acrylate Michael addition reactions have proven useful in programming main-chain liquid crystal elastomers (LCEs). However, the influence of excess acrylate concentration, which is critical to monodomain programming, has not previously been examined with respect to thermomechanical properties in these two-stage LCEs. Previous studies of thiol-acrylate LCEs have focused on polydomain LCEs and/or variation of thiol crosslinking monomers or linear thiol monomers. This study guides the design of monodomain LCE actuators using the two-stage methodology by varying the concentration of mesogenic acrylate monomers from 2 mol% to 45 mol% in stoichiometric excess of thiol. The findings demonstrate a technique to tailor the isotropic transition temperature by 44 °C using identical starting monomers. In contrast to expectations, low amounts of excess acrylate showed excellent fixity (90.4 ± 2.9%), while high amounts of excess acrylate did not hinder actuation strain (87.3 ± 2.3%). Tensile stress-strain properties were influenced by excess acrylate. Linear elastic behavior was observed parallel to the director with modulus increasing from 1.4 to 6.1 MPa. The soft elastic plateau was observed perpendicular to the director with initial modulus and threshold stresses increasing from 0.6 MPa to 2.6 MPa and 14 kPa to 208 kPa, respectively. Overall, this study examines the influence of excess acrylate on mechanical properties of LCE actuators.
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Affiliation(s)
- Daniel R Merkel
- University of Wyoming, Department of Mechanical Engineering, Laramie, WY, USA.
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20
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The Isotropic and Cubic Material Designs. Recovery of the Underlying Microstructures Appearing in the Least Compliant Continuum Bodies. MATERIALS 2017; 10:ma10101137. [PMID: 28954406 PMCID: PMC5666943 DOI: 10.3390/ma10101137] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 11/17/2022]
Abstract
The paper discusses the problem of manufacturability of the minimum compliance designs of the structural elements made of two kinds of inhomogeneous materials: the isotropic and cubic. In both the cases the unit cost of the design is assumed as equal to the trace of the Hooke tensor. The Isotropic Material Design (IMD) delivers the optimal distribution of the bulk and shear moduli within the design domain. The Cubic Material Design (CMD) leads to the optimal material orientation and optimal distribution of the invariant moduli in the body made of the material of cubic symmetry. The present paper proves that the varying underlying microstructures (i.e., the representative volume elements (RVE) constructed of one or two isotropic materials) corresponding to the optimal designs constructed by IMD and CMD methods can be recovered by matching the values of the optimal moduli with the values of the effective moduli of the RVE computed by the theory of homogenization. The CMD method leads to a larger set of results, i.e., the set of pairs of optimal moduli. Moreover, special attention is focused on proper recovery of the microstructures in the auxetic sub-domains of the optimal designs.
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21
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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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22
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Shin J, Kang M, Tsai T, Leal C, Braun PV, Cahill DG. Thermally Functional Liquid Crystal Networks by Magnetic Field Driven Molecular Orientation. ACS Macro Lett 2016; 5:955-960. [PMID: 35607211 DOI: 10.1021/acsmacrolett.6b00475] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aligned liquid crystal networks were synthesized by photopolymerization of liquid crystal monomers in the presence of magnetic fields. Grazing incident wide-angle X-ray scattering was used to characterize the degree of molecular alignment of mesogen chains and time-domain thermoreflectance was used to measure thermal conductivity. Liquid crystal networks with mesogenic units aligned perpendicular and parallel to the substrate exhibit thermal conductivity of 0.34 W m-1 K-1 and 0.22 W m-1 K-1, respectively. The thermal conductivity and orientational order of liquid crystal networks vary as a function of temperature. The thermal conductivity of liquid crystal networks can be manipulated by a magnetic field at above the glass transition temperature (65 °C) where the reduced viscosity enables molecular reorientation on the time scale of 10 min.
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Affiliation(s)
- Jungwoo Shin
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Minjee Kang
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Tsunghan Tsai
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Cecilia Leal
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Paul V. Braun
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - David G. Cahill
- Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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23
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Mossety-Leszczak B, Strachota B, Strachota A, Steinhart M, Šlouf M. The orientation-enhancing effect of diphenyl aluminium phosphate nanorods in a liquid-crystalline epoxy matrix ordered by magnetic field. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Liu K, Pesce D, Ma C, Tuchband M, Shuai M, Chen D, Su J, Liu Q, Gerasimov JY, Kolbe A, Zajaczkowski W, Pisula W, Müllen K, Clark NA, Herrmann A. Solvent-free liquid crystals and liquids based on genetically engineered supercharged polypeptides with high elasticity. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:2459-2465. [PMID: 25732045 DOI: 10.1002/adma.201405182] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 02/11/2015] [Indexed: 06/04/2023]
Abstract
A series of solvent-free elastin-like polypeptide liquid crystals and liquids are developed by electrostatic complexation of supercharged elastin-like polypeptides with surfactants. The smectic mesophases exhibit a high elasticity and the values can be easily tuned by varying the alkyl chain lengths of the surfactants or the lengths of the elastin-like polypeptides.
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Affiliation(s)
- Kai Liu
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747, AG, Groningen, The Netherlands
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25
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Abstract
Liquid crystal elastomers with tunable actuation strain are synthesized with simple techniques that enable complexly patterned actuation.
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Affiliation(s)
- T. H. Ware
- Materials and Manufacturing Directorate
- Air Force Research Laboratory
- Wright-Patterson Air Force Base
- USA
- Azimuth Corporation
| | - T. J. White
- Materials and Manufacturing Directorate
- Air Force Research Laboratory
- Wright-Patterson Air Force Base
- USA
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26
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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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