1
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Gao Y, Wang X, Chen Y. Light-driven soft microrobots based on hydrogels and LCEs: development and prospects. RSC Adv 2024; 14:14278-14288. [PMID: 38694551 PMCID: PMC11062240 DOI: 10.1039/d4ra00495g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/08/2024] [Indexed: 05/04/2024] Open
Abstract
In the daily life of mankind, microrobots can respond to stimulations received and perform different functions, which can be used to complete repetitive or dangerous tasks. Magnetic driving works well in robots that are tens or hundreds of microns in size, but there are big challenges in driving microrobots that are just a few microns in size. Therefore, it is impossible to guarantee the precise drive of microrobots to perform tasks. Acoustic driven micro-nano robot can achieve non-invasive and on-demand movement, and the drive has good biological compatibility, but the drive mode has low resolution and requires expensive experimental equipment. Light-driven robots move by converting light energy into other forms of energy. Light is a renewable, powerful energy source that can be used to transmit energy. Due to the gradual maturity of beam modulation and optical microscope technology, the application of light-driven microrobots has gradually become widespread. Light as a kind of electromagnetic wave, we can change the energy of light by controlling the wavelength and intensity of light. Therefore, the light-driven robot has the advantages of programmable, wireless, high resolution and accurate spatio-temporal control. According to the types of robots, light-driven robots are subdivided into three categories, namely light-driven soft microrobots, photochemical microrobots and 3D printed hard polymer microrobots. In this paper, the driving materials, driving mechanisms and application scenarios of light-driven soft microrobots are reviewed, and their advantages and limitations are discussed. Finally, we prospected the field, pointed out the challenges faced by light-driven soft micro robots and proposed corresponding solutions.
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Affiliation(s)
- Yingnan Gao
- School of Electromechanical and Automotive Engineering, Yantai University Yantai 264005 China
| | - Xiaowen Wang
- School of Electromechanical and Automotive Engineering, Yantai University Yantai 264005 China
| | - Yibao Chen
- School of Electromechanical and Automotive Engineering, Yantai University Yantai 264005 China
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2
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Zhang R, Ma H, Li X, Wang B, Li C, Liao W, Li Y, Han L. The simultaneous control over the alternating sequence and the inner-core position of the mesogenic segments in side-chain liquid crystal polymers. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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3
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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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4
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Carlotti M, Tricinci O, den Hoed F, Palagi S, Mattoli V. Direct laser writing of liquid crystal elastomers oriented by a horizontal electric field. OPEN RESEARCH EUROPE 2021; 1:129. [PMID: 37645193 PMCID: PMC10445945 DOI: 10.12688/openreseurope.14135.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/16/2021] [Indexed: 08/31/2023]
Abstract
Background: The ability to fabricate components capable of performing actuation in a reliable and controlled manner is one of the main research topics in the field of microelectromechanical systems (MEMS). However, the development of these technologies can be limited in many cases by 2D lithographic techniques employed in the fabrication process. Direct Laser Writing (DLW), a 3D microprinting technique based on two-photon polymerization, can offer novel solutions to prepare, both rapidly and reliably, 3D nano- and microstructures of arbitrary complexity. In addition, the use of functional materials in the printing process can result in the fabrication of smart and responsive devices. Methods: In this study, we present a novel methodology for the printing of 3D actuating microelements comprising Liquid Crystal Elastomers (LCEs) obtained by DLW. The alignment of the mesogens was performed using a static electric field (1.7 V/µm) generated by indium-tin oxide (ITO) electrodes patterned directly on the printing substrates. Results: When exposed to a temperature higher than 50°C, the printed microstructures actuated rapidly and reversibly of about 8% in the direction perpendicular to the director. Conclusions: A novel methodology was developed that allows the printing of directional actuators comprising LCEs via DLW. To impart the necessary alignment of the mesogens, a static electric field was applied before the printing process by making use of flat ITO electrodes present on the printing substrates. The resulting microelements showed a reversible change in shape when heated higher than 50 °C.
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Affiliation(s)
- Marco Carlotti
- Center for Materials Interfaces (CMI), Italian Institute of Technology, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Omar Tricinci
- Center for Materials Interfaces (CMI), Italian Institute of Technology, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Frank den Hoed
- Center for Materials Interfaces (CMI), Italian Institute of Technology, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
- Engineering and Technology institute Groningen (ENTEG), University of Groningen, Nijenborgh 4, Groningen, 4747 AG, The Netherlands
| | - Stefano Palagi
- The Biorobotic Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
| | - Virgilio Mattoli
- Center for Materials Interfaces (CMI), Italian Institute of Technology, Viale Rinaldo Piaggio 34, Pontedera, 56025, Italy
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5
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Kim H, Abdelrahman MK, Choi J, Kim H, Maeng J, Wang S, Javed M, Rivera-Tarazona LK, Lee H, Ko SH, Ware TH. From Chaos to Control: Programmable Crack Patterning with Molecular Order in Polymer Substrates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008434. [PMID: 33860580 DOI: 10.1002/adma.202008434] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/31/2021] [Indexed: 06/12/2023]
Abstract
Cracks are typically associated with the failure of materials. However, cracks can also be used to create periodic patterns on the surfaces of materials, as observed in the skin of crocodiles and elephants. In synthetic materials, surface patterns are critical to micro- and nanoscale fabrication processes. Here, a strategy is presented that enables freely programmable patterns of cracks on the surface of a polymer and then uses these cracks to pattern other materials. Cracks form during deposition of a thin film metal on a liquid crystal polymer network (LCN) and follow the spatially patterned molecular order of the polymer. These patterned sub-micrometer scale cracks have an order parameter of 0.98 ± 0.02 and form readily over centimeter-scale areas on the flexible substrates. The patterning of the LCN enables cracks that turn corners, spiral azimuthally, or radiate from a point. Conductive inks can be filled into these oriented cracks, resulting in flexible, anisotropic, and transparent conductors. This materials-based processing approach to patterning cracks enables unprecedented control of the orientation, length, width, and depth of the cracks without costly lithography methods. This approach promises new architectures of electronics, sensors, fluidics, optics, and other devices with micro- and nanoscale features.
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Affiliation(s)
- Hyun Kim
- Sensors and Electron Devices Directorate, CCDC Army Research Laboratory, Adelphi, MD, 20783, USA
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Mustafa K Abdelrahman
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Joonmyung Choi
- Department of Mechanical Design Engineering, Hanyang University, Seoul, 04763, Republic of Korea
- Department of Mechanical Engineering, BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, 15588, Republic of Korea
| | - Hongdeok Kim
- Department of Mechanical Design Engineering, Hanyang University, Seoul, 04763, Republic of Korea
- Department of Mechanical Engineering, BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, 15588, Republic of Korea
| | - Jimin Maeng
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Suitu Wang
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Mahjabeen Javed
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Laura K Rivera-Tarazona
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Habeom Lee
- School of Mechanical Engineering, Pusan National University, Busan, 46241, Republic of Korea
| | - Seung Hwan Ko
- Department of Mechanical Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Institute of Advanced Machines and Design (IAMD) / Institute of Engineering Research, Seoul National University, Seoul, 08826, Republic of Korea
| | - Taylor H Ware
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
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6
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Pedrini A, Virga EG. Ridge energy for thin nematic polymer networks. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:7. [PMID: 33616761 PMCID: PMC7900098 DOI: 10.1140/epje/s10189-021-00012-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/23/2020] [Indexed: 06/10/2023]
Abstract
Minimizing the elastic free energy of a thin sheet of nematic polymer network among smooth isometric immersions is the strategy purported by the mainstream theory. In this paper, we broaden the class of admissible spontaneous deformations: we consider ridged isometric immersions, which can cause a sharp ridge in the immersed surfaces. We propose a model to compute the extra energy distributed along such ridges. This energy comes from bending; it is shown under what circumstances it scales quadratically with the sheet's thickness, falling just in between stretching and bending energies. We put our theory to the test by studying the spontaneous deformation of a disk on which a radial hedgehog was imprinted at the time of crosslinking. We predict the number of folds that develop in terms of the degree of order induced in the material by external agents (such as heat and illumination).
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Affiliation(s)
- Andrea Pedrini
- Dipartimento di Matematica, Università di Pavia, Via Ferrata 5, 27100 Pavia, Italy
| | - Epifanio G. Virga
- Dipartimento di Matematica, Università di Pavia, Via Ferrata 5, 27100 Pavia, Italy
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7
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Karausta A, Kocaman C, Bukusoglu E. Controlling the shapes and internal complexity of the polymeric particles using liquid crystal-templates confined into microwells. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Moon J, Chung H, Cho M. Combined coarse-grained molecular dynamics and finite-element study of light-activated deformation of photoresponsive polymers. Phys Rev E 2021; 103:012703. [PMID: 33601526 DOI: 10.1103/physreve.103.012703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 12/22/2020] [Indexed: 11/07/2022]
Abstract
The azobenzene-containing crosslinked liquid crystalline polymer is a potential candidate for a stimuli-responsive soft robot, as it provides contactless actuation without the implementation of any separate component. For facilitating practical applications of this novel material, complicated and predefined motions have been realized by tailoring the chemical structure of the polymer network. However, conventional multiscale mechanical analysis, which utilizes the all-atom molecular dynamics to represent a microscopic model, is unsuitable for handling diverse material design parameters due to excessive computational costs. Hence, a multiscale optomechanical simulation framework, which combines the coarse-grained molecular dynamics (CG MD) and the finite-element (FE) method, is developed in this study. The CG MD simulation satisfactorily reproduces the light-induced phase transition and photosoftening effect on the mechanical properties. In particular, using the mesoscale analysis, the presented methodology can treat diverse morphology parameters (liquid crystal phase, spacer length, and crosslinking density) to observe the associated photodeformations. The photostrain and elastic modulus profiles in terms of photoisomerization ratio are implemented into the continuum-scale governing equation, which is based on the neoclassical elasticity theory. To efficiently reflect the light-induced large rotations of liquid crystal mesogens and the corresponding geometric nonlinearity, a corotational formulation is employed in the FE shell model. We examine the mesostructural-morphology-dependent photobending deformations of the nematic and smectic photoresponsive polymers (PRPs). In addition, the mesoscopic-texture-mediated unique 3D deformations are investigated by modeling the topological defects. This study offers insight into the engineering of PRP materials for designing the mechanical motions of smart actuators.
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Affiliation(s)
- Junghwan Moon
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Republic of Korea
| | - Hayoung Chung
- School of Mechanical, Aerospace, and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Maenghyo Cho
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Republic of Korea.,Division of Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea
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9
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Ozenda O, Sonnet AM, Virga EG. A blend of stretching and bending in nematic polymer networks. SOFT MATTER 2020; 16:8877-8892. [PMID: 33026035 DOI: 10.1039/d0sm00642d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nematic polymer networks are (heat and light) activable materials, which combine the features of rubber and nematic liquid crystals. When only the stretching energy of a thin sheet of nematic polymer network is minimized, the intrinsic (Gaussian) curvature of the shape it takes upon (thermal or optical) actuation is determined. This, unfortunately, produces a multitude of possible shapes, for which we need a selection criterion, which may only be provided by a correcting bending energy depending on the extrinsic curvatures of the deformed shape. The literature has so far offered approximate corrections depending on the mean curvature. In this paper, we derive the appropriate bending energy for a sheet of nematic polymer network from the celebrated neo-classical energy of nematic elastomers in three space dimensions. This task is performed via a dimension reduction based on a modified Kirchhoff-Love hypothesis, which withstands the criticism of more sophisticated analytical tools. The result is a surface elastic free-energy density where stretching and bending are blended together; they may or may not be length-separated, and should be minimized together. The extrinsic curvatures of the deformed shape not only feature in the bending energy through the mean curvature, but also through the relative orientation of the nematic director in the frame of the directions of principal curvatures.
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Affiliation(s)
- Olivier Ozenda
- Dipartimento di Matematica, Università di Pavia, Via Ferrata 5, 27100 Pavia, Italy.
| | - André M Sonnet
- Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, Glasgow G1 1XH, UK.
| | - Epifanio G Virga
- Dipartimento di Matematica, Università di Pavia, Via Ferrata 5, 27100 Pavia, Italy.
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10
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Kuang X, Roach DJ, Hamel CM, Yu K, Qi HJ. Materials, design, and fabrication of shape programmable polymers. ACTA ACUST UNITED AC 2020. [DOI: 10.1088/2399-7532/aba1d9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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Miao W, Zou W, Jin B, Ni C, Zheng N, Zhao Q, Xie T. On demand shape memory polymer via light regulated topological defects in a dynamic covalent network. Nat Commun 2020; 11:4257. [PMID: 32848146 PMCID: PMC7450050 DOI: 10.1038/s41467-020-18116-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/29/2020] [Indexed: 11/09/2022] Open
Abstract
The ability to undergo bond exchange in a dynamic covalent polymer network has brought many benefits not offered by classical thermoplastic and thermoset polymers. Despite the bond exchangeability, the overall network topologies for existing dynamic networks typically cannot be altered, limiting their potential expansion into unexplored territories. By harnessing topological defects inherent in any real polymer network, we show herein a general design that allows a dynamic network to undergo rearrangement to distinctive topologies. The use of a light triggered catalyst further allows spatio-temporal regulation of the network topology, leading to an unusual opportunity to program polymer properties. Applying this strategy to functional shape memory networks yields custom designable multi-shape and reversible shape memory characteristics. This molecular principle expands the design versatility for network polymers, with broad implications in many other areas including soft robotics, flexible electronics, and medical devices.
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Affiliation(s)
- Wusha Miao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Weike Zou
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Binjie Jin
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Chujun Ni
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Ning Zheng
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Qian Zhao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, 311215, Hangzhou, China
| | - Tao Xie
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China.
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, 311215, Hangzhou, China.
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12
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Lee Y, Choi S, Kang BG, Ahn SK. Effect of Isomeric Amine Chain Extenders and Crosslink Density on the Properties of Liquid Crystal Elastomers. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3094. [PMID: 32664370 PMCID: PMC7412247 DOI: 10.3390/ma13143094] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/02/2020] [Accepted: 07/08/2020] [Indexed: 12/25/2022]
Abstract
Among the various types of shape changing materials, liquid crystal elastomers (LCEs) have received significant attention as they can undergo programmed and reversible shape transformations. The molecular engineering of LCEs is the key to manipulating their phase transition, mechanical properties, and actuation performance. In this work, LCEs containing three different types of butyl groups (n-, iso-, and sec-butyl) in the side chain were synthesized, and the effect of isomeric amine chain extenders on the thermal, mechanical, and actuation properties of the resulting LCEs was investigated. Because of the considerably low reactivity of the sec-butyl group toward the diacrylate in the LC monomer, only a densely crosslinked LCE was synthesized. Most interestingly, the mechanical properties, actuation temperature, and blocking stress of the LCEs comprising isobutyl groups were higher than those of the LCEs comprising n-butyl groups. This difference was attributed to the presence of branches in the LCEs with isobutyl groups, which resulted in a tighter molecular packing and reduced the free volume. Our results suggest a facile and effective method for synthesizing LCEs with tailored mechanical and actuation properties by the choice of chain extenders, which may advance the development of soft actuators for a variety of applications in aerospace, medicine, and optics.
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Affiliation(s)
- Yoojin Lee
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea; (Y.L.); (S.C.)
| | - Subi Choi
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea; (Y.L.); (S.C.)
| | - Beom-Goo Kang
- Department of Chemical Engineering, Soongsil University, Seoul 06978, Korea
| | - Suk-kyun Ahn
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea; (Y.L.); (S.C.)
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13
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McCracken JM, Donovan BR, White TJ. Materials as Machines. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906564. [PMID: 32133704 DOI: 10.1002/adma.201906564] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/19/2019] [Indexed: 05/23/2023]
Abstract
Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walking, crawling, swimming, and flying). Key functional considerations of responsive materials in machine implementations are response time, cyclability (frequency and ruggedness), sizing, payload capacity, amenability to mechanical programming, performance in extreme environments, and autonomy. This review summarizes the material transformation mechanisms, mechanical design, and robotic integration of responsive materials including shape memory alloys (SMAs), piezoelectrics, dielectric elastomer actuators (DEAs), ionic electroactive polymers (IEAPs), pneumatics and hydraulics systems, shape memory polymers (SMPs), hydrogels, and liquid crystalline elastomers (LCEs) and networks (LCNs). Structural and geometrical fabrication of these materials as wires, coils, films, tubes, cones, unimorphs, bimorphs, and printed elements enables differentiated mechanical responses and consistently enables and extends functional use.
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Affiliation(s)
- Joselle M McCracken
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Brian R Donovan
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
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14
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Lee J, Guo Y, Choi YJ, Jung S, Seol D, Choi S, Kim JH, Kim Y, Jeong KU, Ahn SK. Mechanically programmed 2D and 3D liquid crystal elastomers at macro- and microscale via two-step photocrosslinking. SOFT MATTER 2020; 16:2695-2705. [PMID: 32057062 DOI: 10.1039/c9sm02237f] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Liquid crystal elastomers (LCEs) are a unique class of active materials with the largest known reversible shape transformation in the solid state. The shape change of LCEs is directed by programming their molecular orientation, and therefore, several strategies to control LC alignment have been developed. Although mechanical alignment coupled with a two-step crosslinking is commonly adopted for uniaxially-aligned monodomain LCE synthesis, the fabrication of 3D-shaped LCEs at the macro- and microscale has been rarely accomplished. Here, we report a facile processing method for fabricating 2D and 3D-shaped LCEs at the macro- and microscales at room temperature by mechanically programming (i.e., stretching, pressing, embossing and UV-imprinting) the polydomain LCE, and subsequent photocrosslinking. The programmed LCEs exhibited a reversible shape change when exposed to thermal and chemical stimuli. Besides the programmed shape changes, the actuation strain can also be preprogrammed by adjusting the extent of elongation of a polydomain LCE. Furthermore, the LCE micropillar arrays prepared by UV-imprinting displayed a substantial change in pillar height in a reversible manner during thermal actuation. Our convenient method for fabricating reversible 2D and 3D-shaped LCEs from commercially available materials may expedite the potential applications of LCEs in actuators, soft robots, smart coatings, tunable optics and medicine.
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Affiliation(s)
- Jieun Lee
- Department of Polymer Science and Engineering, Pusan National University, Busan, 46241, Korea.
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15
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Jeon SJ, Hayward RC. Simultaneous control of Gaussian curvature and buckling direction by swelling of asymmetric trilayer hydrogel hybrids. SOFT MATTER 2020; 16:688-694. [PMID: 31815272 DOI: 10.1039/c9sm01922g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Trilayer polymer films consisting of a thermoresponsive hydrogel, poly(diethyl acrylamide) (PDEAM), sandwiched by rigid layers of a glassy polymer, poly(para-methylstyrene) (PpMS), patterned into parallel striped features are prepared and used to drive temperature-responsive reversible anisotropic expansion. Significant swelling occurs along the direction perpendicular to the stripes, while very little swelling is observed along the direction parallel to the stripes, leading to an overall swelling anisotropy of 1.17. Introducing a difference Δ in the widths of the stripes on the top to bottom surfaces causes the films to roll upon swelling, where both the magnitude and sign of the resulting curvature can be controlled by varying Δ. Using patterns of concentric circular lines (analogous to +1 defects in liquid crystalline polymers), we demonstrate the swelling-induced formation of cone-like shapes, where the buckling direction of each unit can be programmed through local variations in Δ. This trilayer concept provides a simple way to simultaneously control both the Gaussian curvature and direction of buckling in shape-morphing hydrogels, with advantages for accessing smaller length-scales compared to existing methods.
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Affiliation(s)
- Seog-Jin Jeon
- Department of Polymer Science and Engineering, Kumoh National Institute of Technology, Gumi, Gyeongbuk 39177, South Korea
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16
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Rastogi P, Njuguna J, Kandasubramanian B. Exploration of elastomeric and polymeric liquid crystals with photothermal actuation: A review. Eur Polym J 2019. [DOI: 10.1016/j.eurpolymj.2019.109287] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Kubo S, Kumagai M, Kawatsuki N, Nakagawa M. Photoinduced Reorientation in Thin Films of a Nematic Liquid Crystalline Polymer Anchored to Interfaces and Enhancement Using Small Liquid Crystalline Molecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14222-14229. [PMID: 31592666 DOI: 10.1021/acs.langmuir.9b02673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The photoinduced reorientation of the side-chain mesogens in nematic liquid crystalline (LC) polymer thin films triggered by the axis-selective photo-Fries rearrangements of side-chain phenyl benzoate moieties is studied to understand the regulation of the anisotropic nanostructures supported by LC polymers. The influence of the substrate surface in anchoring the side-chain mesogens near the interfaces is examined by comparing the reorientation of 30- and 120-nm-thick films. Irradiation with linearly polarized ultraviolet (UV) light and subsequent annealing causes the side-chain mesogen reorientation to align perpendicular to the electric field of the incident UV light. The inplane order in the 30-nm-thick films is lower than that in the 120-nm ones. On the other hand, the annealing period required for mesogen alignment is independent of the film thickness. It is suggested that the substrate surfaces anchor the LC mesogens to fix their orientation, rather than slowing down the reorientational motion. In addition, it is demonstrated that small LC molecules miscible with the nematic LC polymer enhance photoinduced reorientation through cooperative molecular interaction with the side-chain mesogens, remarkably accelerating the orientation and improving the inplane order of the unidirectionally aligned mesogens.
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Affiliation(s)
- Shoichi Kubo
- National Institute for Materials Science , 1-2-1 Sengen , Tsukuba , Ibaraki 305-0047 , Japan
| | - Mari Kumagai
- Institute of Multidisciplinary Research for Advanced Materials , Tohoku University , 2-1-1 Katahira , Aoba-ku, Sendai , Miyagi 980-8577 , Japan
| | - Nobuhiro Kawatsuki
- Department of Applied Chemistry, Graduate School of Engineering , University of Hyogo , 2167 Shosha , Himeji 671-2280 , Japan
| | - Masaru Nakagawa
- Institute of Multidisciplinary Research for Advanced Materials , Tohoku University , 2-1-1 Katahira , Aoba-ku, Sendai , Miyagi 980-8577 , Japan
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18
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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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19
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Guo Y, Lee J, Son J, Ahn SK, Carrillo JMY, Sumpter BG. Decoding Liquid Crystal Oligomer Phase Transitions: Toward Molecularly Engineered Shape Changing Materials. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01218] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Yuanhang Guo
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea
| | - Jieun Lee
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea
| | - Jinha Son
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea
| | - Suk-kyun Ahn
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Korea
| | - Jan-Michael Y. Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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20
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He Z, Tan G, Chanda D, Wu ST. Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]. OPTICS EXPRESS 2019; 27:11472-11491. [PMID: 31052991 DOI: 10.1364/oe.27.011472] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
In addition to displays, liquid crystals (LCs) have also found widespread applications in photonic devices, such as adaptive lens, adaptive optics, and sensors, because of their responses to electric field, temperature, and light. As the fabrication technique advances, more sophisticated devices can be designed and created. In this review, we report recent advances of two-photon polymerization-based direct-laser writing enabled LC devices. Firstly, we describe the basic working principle of two-photon polymerization. With this powerful fabrication technique, we can generate anchoring energy by surface morphology to align LC directors on different form factors. To prove this concept, we demonstrate LC alignment on planar, curvilinear surfaces as well as in three-dimensional volumes. Based on the results, we further propose a novel, ultra-broadband, twisted-nematic diffractive waveplate that can potentially be fulfilled by this technique. Next, we briefly discuss the current status of direct-laser writing on LC reactive mesogens and its potential applications. Finally, we present two design challenges: fabrication yield and polymer relaxation/deformation, remaining to be overcome.
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21
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Moon J, Kim B, Choi J, Cho M. Multiscale Study of the Relationship between Photoisomerization and Mechanical Behavior of Azo-Polymer Based on the Coarse-Grained Molecular Dynamics Simulation. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02535] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | | | - Joonmyung Choi
- Department of Mechanical Engineering, Hanyang University, Ansan, Gyeonggi-do, Republic of Korea
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22
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Karausta A, Bukusoglu E. Liquid Crystal-Templated Synthesis of Mesoporous Membranes with Predetermined Pore Alignment. ACS APPLIED MATERIALS & INTERFACES 2018; 10:33484-33492. [PMID: 30198253 DOI: 10.1021/acsami.8b14121] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We demonstrate that polymeric films templated from liquid crystals (LCs) provide basic design principles for the synthesis of mesoporous films with predetermined pore alignment. Specifically, we used LC mixtures of reactive [4-(3-acryloyoxypropyloxy) benzoic acid 2-methyl-1,4-phenylene ester (RM257)] and nonreactive [4-cyano-4'-pentylbiphenyl (5CB)] mesogens confined in film geometries. The LC alignment was maintained by functionalization of the surfaces contacting the films during polymerization. Through photopolymerization followed by extraction of the unreacted mesogens, films of area in the order of 10 cm2 were obtained. We found that, when restricted to an area either through a mechanical or a configurational constraint, open and accessible pores were incorporated into the films. The average direction of the pores could be determined by the LC director during polymerization, and the average diameter of the pores can be tuned in the range of 10-40 nm by varying the reactive monomer concentration. The polymeric films synthesized here can potentially be used for the ultrafiltration purposes. We demonstrated successful separations of proteins and nanoparticles from aqueous media using the polymeric films. The films exhibited 2 orders of magnitude higher flux when the pores were aligned parallel to the permeate direction compared to the perpendicular direction. Overall, the outcomes of this study provide basic tools for the synthesis of porous polymeric films with predetermined pore directions that can potentially be suitable for separations, drug delivery, catalysts, and so forth.
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Affiliation(s)
- Aslı Karausta
- Chemical Engineering Department , Middle East Technical University , Ankara 06800 , Turkey
| | - Emre Bukusoglu
- Chemical Engineering Department , Middle East Technical University , Ankara 06800 , Turkey
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23
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Zhang G, Peng W, Wu J, Zhao Q, Xie T. Digital coding of mechanical stress in a dynamic covalent shape memory polymer network. Nat Commun 2018; 9:4002. [PMID: 30275498 PMCID: PMC6167378 DOI: 10.1038/s41467-018-06420-w] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/17/2018] [Indexed: 11/20/2022] Open
Abstract
Controlling stresses in materials presents many unusual opportunities for their engineering applications. The potential for current approaches is severely limited by the intrinsic tie between the stress and the geometric shape. Here, we report a material concept that allows stress management in a highly efficient digital manner while decoupling the stress and the geometric shape. This is realized in a dynamic covalent shape memory polymer network, for which the elastic shape memory sets the baseline stress level and maintains the geometric shape while the plasticity enabled by the dynamic bond exchange allows stress tuning. With a digital gray scale photothermal mechanism, any arbitrarily defined stress distribution can be created in a free-standing polymer film. The naturally invisible stresses can be further visualized as mechanical colors under polarized light, revealing its potential for encoding hidden information. Our approach expands the technological potential in many areas for which stresses are relevant.
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Affiliation(s)
- Guogao Zhang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Wenjun Peng
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jingjun Wu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Qian Zhao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Tao Xie
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
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24
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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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25
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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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26
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Kowalski BA, Mostajeran C, Godman NP, Warner M, White TJ. Curvature by design and on demand in liquid crystal elastomers. Phys Rev E 2018; 97:012504. [PMID: 29448377 DOI: 10.1103/physreve.97.012504] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Indexed: 12/27/2022]
Abstract
The shape of liquid crystalline elastomers (LCEs) with spatial variation in the director orientation can be transformed by exposure to a stimulus. Here, informed by previously reported analytical treatments, we prepare complex spiral patterns imprinted into LCEs and quantify the resulting shape transformation. Quantification of the stimuli-induced shapes reveals good agreement between predicted and experimentally observed curvatures. We conclude this communication by reporting a design strategy to allow LCE films to be anchored at their external boundaries onto rigid substrates without incurring internal, mechanical-mismatch stresses upon actuation, a critical advance to the realization of shape transformation of LCEs in practical device applications.
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Affiliation(s)
- B A Kowalski
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, USA.,Azimuth Corporation, Beavercreek, Ohio 45431, USA
| | - C Mostajeran
- Department of Engineering, University of Cambridge CB2 1PZ, United Kingdom
| | - N P Godman
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - M Warner
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - T J White
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, USA
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27
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Meng X, Pan H, Zhu C, Chen Z, Lu T, Xu D, Li Y, Zhu S. Coupled Chiral Structure in Graphene-Based Film for Ultrahigh Thermal Conductivity in Both In-Plane and Through-Plane Directions. ACS APPLIED MATERIALS & INTERFACES 2018; 10:22611-22622. [PMID: 29888597 DOI: 10.1021/acsami.8b05514] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The development of high-performance thermal management materials to dissipate excessive heat both in plane and through plane is of special interest to maintain efficient operation and prolong the life of electronic devices. Herein, we designed and constructed a graphene-based composite film, which contains chiral liquid crystals (cellulose nanocrystals, CNCs) inside graphene oxide (GO). The composite film was prepared by annealing and compacting of self-assembled GO-CNC, which contains chiral smectic liquid crystal structures. The helical arranged nanorods of carbonized CNC act as in-plane connections, which bridge neighboring graphene sheets. More interestingly, the chiral structures also act as through-plane connections, which bridge the upper and lower graphene layers. As a result, the graphene-based composite film shows extraordinary thermal conductivity, in both in-plane (1820.4 W m-1 K-1) and through-plane (4.596 W m-1 K-1) directions. As a thermal management material, the heat dissipation and transportation behaviors of the composite film were investigated using a self-heating system and the results showed that the real-time temperature of the heater covered with the film was 44.5 °C lower than a naked heater. The prepared film shows a much higher efficiency of heat transportation than the commonly used thermal conductive Cu foil. Additionally, this graphene-based composite film exhibits excellent mechanical strength of 31.6 MPa and an electrical conductivity of 667.4 S cm-1. The strategy reported here may open a new avenue to the development of high-performance thermal management films.
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Affiliation(s)
- Xin Meng
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Hui Pan
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Chengling Zhu
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Zhixin Chen
- School of Mechanical, Materials & Mechatronics Engineering , University of Wollongong , Wollongong , NSW 2522 , Australia
| | - Tao Lu
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Da Xu
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Yao Li
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Shenmin Zhu
- State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , Shanghai 200240 , China
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28
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Guin T, Settle MJ, Kowalski BA, Auguste AD, Beblo RV, Reich GW, White TJ. Layered liquid crystal elastomer actuators. Nat Commun 2018; 9:2531. [PMID: 29955053 PMCID: PMC6023890 DOI: 10.1038/s41467-018-04911-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/29/2018] [Indexed: 11/25/2022] Open
Abstract
Liquid crystalline elastomers (LCEs) are soft, anisotropic materials that exhibit large shape transformations when subjected to various stimuli. Here we demonstrate a facile approach to enhance the out-of-plane work capacity of these materials by an order of magnitude, to nearly 20 J/kg. The enhancement in force output is enabled by the development of a room temperature polymerizable composition used both to prepare individual films, organized via directed self-assembly to retain arrays of topological defect profiles, as well as act as an adhesive to combine the LCE layers. The material actuator is shown to displace a load >2500× heavier than its own weight nearly 0.5 mm.
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Affiliation(s)
- Tyler Guin
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- Azimuth Corporation, 4027 Colonel Glenn Hwy, Beavercreek, OH, 45431, USA
| | - Michael J Settle
- Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- University of Dayton Research Institute, 1700 S Patterson Blvd, Dayton, OH, 45469, USA
| | - Benjamin A Kowalski
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- Azimuth Corporation, 4027 Colonel Glenn Hwy, Beavercreek, OH, 45431, USA
| | - Anesia D Auguste
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
| | - Richard V Beblo
- Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, OH, 45433, USA
- University of Dayton Research Institute, 1700 S Patterson Blvd, Dayton, OH, 45469, USA
| | - Gregory W Reich
- Air Force Research Laboratory, Aerospace Systems 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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29
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Zeng H, Wasylczyk P, Wiersma DS, Priimagi A. Light Robots: Bridging the Gap between Microrobotics and Photomechanics in Soft Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1703554. [PMID: 29067734 DOI: 10.1002/adma.201703554] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/30/2017] [Indexed: 05/23/2023]
Abstract
For decades, roboticists have focused their efforts on rigid systems that enable programmable, automated action, and sophisticated control with maximal movement precision and speed. Meanwhile, material scientists have sought compounds and fabrication strategies to devise polymeric actuators that are small, soft, adaptive, and stimuli-responsive. Merging these two fields has given birth to a new class of devices-soft microrobots that, by combining concepts from microrobotics and stimuli-responsive materials research, provide several advantages in a miniature form: external, remotely controllable power supply, adaptive motion, and human-friendly interaction, with device design and action often inspired by biological systems. Herein, recent progress in soft microrobotics is highlighted based on light-responsive liquid-crystal elastomers and polymer networks, focusing on photomobile devices such as walkers, swimmers, and mechanical oscillators, which may ultimately lead to flying microrobots. Finally, self-regulated actuation is proposed as a new pathway toward fully autonomous, intelligent light robots of the future.
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Affiliation(s)
- Hao Zeng
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI, 33101, Tampere, Finland
| | - Piotr Wasylczyk
- Photonic Nanostructure Facility, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
| | - Diederik S Wiersma
- European Laboratory for Non Linear Spectroscopy (LENS), University of Florence and INRIM, via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
| | - Arri Priimagi
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI, 33101, Tampere, Finland
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30
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Martella D, Parmeggiani C. Advances in Cell Scaffolds for Tissue Engineering: The Value of Liquid Crystalline Elastomers. Chemistry 2018; 24:12206-12220. [DOI: 10.1002/chem.201800477] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Daniele Martella
- Chemistry Department “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 Sesto Fiorentino Italy
- CNR-INO; European Laboratory for Non-Linear Spectroscopy (LENS); University of Florence; via Nello Carrara 1 Sesto Fiorentino Italy
| | - Camilla Parmeggiani
- Chemistry Department “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 Sesto Fiorentino Italy
- CNR-INO; European Laboratory for Non-Linear Spectroscopy (LENS); University of Florence; via Nello Carrara 1 Sesto Fiorentino Italy
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31
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Yang R, Zhao Y. Multitemperature Memory Actuation of a Liquid Crystal Polymer Network over a Broad Nematic-Isotropic Phase Transition Induced by Large Strain. ACS Macro Lett 2018; 7:353-357. [PMID: 35632911 DOI: 10.1021/acsmacrolett.8b00089] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The shape change of a polymer actuator based on liquid crystal network (LCN) generally occurs over a relatively sharp LC-isotropic phase transition. Reported herein is the discovery of an unusual phenomenon and the enabled actuation control for LCN. The smectic phase of a LCN with mesogenic moieties on the chain backbone can be suppressed by high elongation of the specimen, which gives rise to a broad nematic-isotropic phase transition. Consequently, the actuation force and related shape of the actuator can be activated to a given degree by easily varying the temperature over a wide range (35 K for LCN prepared with 500% strain) to adjust the proportion of the order-disorder phase transition. This reversible multitemperature memory actuation can translate into many stable and interconvertible shapes with one single LCN actuator.
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Affiliation(s)
- Rong Yang
- Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, School of Materials Science and Engineering, Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou, 213164, People’s Republic of China
- Département de chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Yue Zhao
- Département de chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
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Guin T, Kowalski BA, Rao R, Auguste AD, Grabowski CA, Lloyd PF, Tondiglia VP, Maruyama B, Vaia RA, White TJ. Electrical Control of Shape in Voxelated Liquid Crystalline Polymer Nanocomposites. ACS APPLIED MATERIALS & INTERFACES 2018; 10:1187-1194. [PMID: 29239172 DOI: 10.1021/acsami.7b13814] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Liquid crystal elastomers (LCEs) exhibit anisotropic mechanical, thermal, and optical properties. The director orientation within an LCE can be spatially localized into voxels [three-dimensional (3-D) volume elements] via photoalignment surfaces. Here, we prepare nanocomposites in which both the orientation of the LCE and single-walled carbon nanotube (SWNT) are locally and arbitrarily oriented in discrete voxels. The addition of SWNTs increases the stiffness of the LCE in the orientation direction, yielding a material with a 5:1 directional modulus contrast. The inclusion of SWNT modifies the thermomechanical response and, most notably, is shown to enable distinctive electromechanical deformation of the nanocomposite. Specifically, the incorporation of SWNTs sensitizes the LCE to a dc field, enabling uniaxial electrostriction along the orientation direction. We demonstrate that localized orientation of the LCE and SWNT allows complex 3-D shape transformations to be electrically triggered. Initial experiments indicate that the SWNT-polymer interfaces play a crucial role in enabling the electrostriction reported herein.
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Affiliation(s)
- Tyler Guin
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
- Azimuth Corporation , 4027 Colonel Glenn Highway, Beavercreek, Ohio 45431, United States
| | - Benjamin A Kowalski
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
- Azimuth Corporation , 4027 Colonel Glenn Highway, Beavercreek, Ohio 45431, United States
| | - Rahul Rao
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Anesia D Auguste
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Christopher A Grabowski
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
- UES, Inc. , 4401 Dayton Xenia Rd, Beavercreek, Ohio 45432, United States
| | - Pamela F Lloyd
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
- UES, Inc. , 4401 Dayton Xenia Rd, Beavercreek, Ohio 45432, United States
| | - Vincent P Tondiglia
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
- Azimuth Corporation , 4027 Colonel Glenn Highway, Beavercreek, Ohio 45431, United States
| | - Benji Maruyama
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Richard A Vaia
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Timothy J White
- Air Force Research Laboratory, Materials and Manufacturing Directorate , 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433-7750, United States
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Belmonte A, Lama GC, Gentile G, Cerruti P, Ambrogi V, Fernández-Francos X, De la Flor S. Thermally-triggered free-standing shape-memory actuators. Eur Polym J 2017. [DOI: 10.1016/j.eurpolymj.2017.10.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Nocentini S, Martella D, Wiersma DS, Parmeggiani C. Beam steering by liquid crystal elastomer fibres. SOFT MATTER 2017; 13:8590-8596. [PMID: 29105720 DOI: 10.1039/c7sm02063e] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The problem of utilizing a laser beam as an information vehicle and dividing it into different channels is an open problem in the telecommunication field. The switching of a signal into different ports has been demonstrated, to date, by employing complex devices and mechanisms such as the electro optic effect, microelectromechanical system (MEMS) mirrors, or liquid crystal-based spatial light modulators (SLMs). We present here a simple device, namely a mirror held by a liquid crystal elastomer (LCE) fibre, as an optically and remotely driven beam steerer. In fact, a considered signal (laser beam) can be addressed in every in-plane direction by controlling the fibre and mirror rotation, i.e., the deflected probe beam angle. Such movement is possible due to the preparation of LCE fibres able to rotate and contract under a selective light stimulus. By adjusting the irradiation stimulus power, elastic fibres are able to rotate with a specific angle, performing more than one complete revolution around their axis. The described movement is perfectly reversible as soon as the stimulus is removed.
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Affiliation(s)
- S Nocentini
- European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.
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Godman NP, Kowalski BA, Auguste AD, Koerner H, White TJ. Synthesis of Elastomeric Liquid Crystalline Polymer Networks via Chain Transfer. ACS Macro Lett 2017; 6:1290-1295. [PMID: 35650784 DOI: 10.1021/acsmacrolett.7b00822] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Materials capable of complex shape changes have broad reaching applications spanning biomimetic devices, componentless actuators, artificial muscles, and haptic displays. Liquid crystal elastomers (LCE) are a class of shape programmable materials which display anisotropic mechanical deformations in response external stimuli. This work details a synthetic strategy to quickly and efficiently prepare LCEs through the usage of chain transfer agents (CTA). The polyacrylate materials described herein exhibit large, reversible shape changes with strains greater 475%, rivalling properties observed in polysiloxane-based networks. The approach reported here is distinguished in that the materials chemistry is readily amenable to surface alignment techniques. The facile nature of the materials chemistry and the compatibility of these materials with directed self-assembly methods could further enable paradigm shifting end uses as designer substrates for flexible electronics or as actuating surfaces.
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Affiliation(s)
- Nicholas P. Godman
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7750, United States
| | - Benjamin A. Kowalski
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7750, United States
- Azimuth Corporation, 4027 Colonel Glenn Highway, Beavercreek, Ohio 45431, United States
| | - Anesia D. Auguste
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7750, United States
| | - Hilmar Koerner
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7750, United States
| | - Timothy J. White
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7750, United States
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Yang R, Zhao Y. Non-Uniform Optical Inscription of Actuation Domains in a Liquid Crystal Polymer of Uniaxial Orientation: An Approach to Complex and Programmable Shape Changes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709528] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Rong Yang
- Département de chimie; Université de Sherbrooke; Sherbrooke Québec J1K 2R1 Canada
- Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials; School of Materials Science and Engineering; Changzhou University; Changzhou 213164 P.R. China
| | - Yue Zhao
- Département de chimie; Université de Sherbrooke; Sherbrooke Québec J1K 2R1 Canada
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Yang R, Zhao Y. Non-Uniform Optical Inscription of Actuation Domains in a Liquid Crystal Polymer of Uniaxial Orientation: An Approach to Complex and Programmable Shape Changes. Angew Chem Int Ed Engl 2017; 56:14202-14206. [DOI: 10.1002/anie.201709528] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Rong Yang
- Département de chimie; Université de Sherbrooke; Sherbrooke Québec J1K 2R1 Canada
- Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials; School of Materials Science and Engineering; Changzhou University; Changzhou 213164 P.R. China
| | - Yue Zhao
- Département de chimie; Université de Sherbrooke; Sherbrooke Québec J1K 2R1 Canada
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