1
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van Hazendonk L, Khalil ZJ, van Grondelle W, Wijkhuijs LEA, Schreur-Piet I, Debije MG, Friedrich H. Hot Fingers: Individually Addressable Graphene-Heater Actuated Liquid Crystal Grippers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:32739-32747. [PMID: 38869014 PMCID: PMC11212024 DOI: 10.1021/acsami.4c06130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/23/2024] [Accepted: 06/03/2024] [Indexed: 06/14/2024]
Abstract
Liquid crystal-based actuators are receiving increased attention for their applications in wearables and biomedical or surgical devices, with selective actuation of individual parts/fingers still being in its infancy. This work presents the design and realization of two gripper devices with four individually addressable liquid-crystal network (LCN) actuators thermally driven via printed graphene-based heating elements. The resistive heat causes the all-organic actuator to bend due to anisotropic volume expansions of the splay-aligned sample. A heat transfer model that includes all relevant interfaces is presented and verified via thermal imaging, which provides good estimates of dimensions, power production, and resistance required to reach the desired temperature for actuation while maintaining safe electrical potentials. The LCN films displace up to 11 mm with a bending force of 1.10 mN upon application of 0-15 V potentials. The robustness of the LCN finger is confirmed by repetitive on/off switching for 500 cycles. Actuators are assembled into two prototypes able to grip and lift objects of small weights (70-100 mg) and perform complex actions by individually controlling one of the device's fingers to grip an additional object. Selective actuation of parts in soft robotic devices will enable more complex motions and actions to be performed.
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Affiliation(s)
- Laura
S. van Hazendonk
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Zafeiris J. Khalil
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Wilko van Grondelle
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Levina E. A. Wijkhuijs
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Ingeborg Schreur-Piet
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Center
for Multiscale Electron Microscopy, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Michael G. Debije
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Stimuli-responsive
Functional Materials and Devices (SFD), Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
| | - Heiner Friedrich
- Laboratory
of Physical Chemistry, Department of Chemical
Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
- Center
for Multiscale Electron Microscopy, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands
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2
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Berrow SR, Mandle RJ, Raistrick T, Reynolds M, Gleeson HF. Toward Monodomain Nematic Liquid Crystal Elastomers of Arbitrary Thickness through PET-RAFT Polymerization. Macromolecules 2024; 57:5218-5229. [PMID: 38882196 PMCID: PMC11171763 DOI: 10.1021/acs.macromol.4c00245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/21/2024] [Accepted: 05/16/2024] [Indexed: 06/18/2024]
Abstract
Liquid crystal elastomers (LCEs) are polymeric materials that are proposed for a range of applications. However, to reach their full potential, it is desirable to have as much flexibility as possible in terms of the sample dimensions, while maintaining well-defined alignment. In this work, photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization is applied to the synthesis of LCEs for the first time. An initial LCE layer (∼100 μm thickness) is partially cured before a second layer of the precursor mixture is added. The curing reaction is then resumed and is observed by FTIR to complete within 15 min of irradiation, yielding samples of increased thickness. Monodomain samples that exhibit an auxetic response and are of thickness 250-300 μm are consistently achieved. All samples are characterized thermally, mechanically, and in terms of their order parameters. The LCEs have physical properties comparable to those of analogous LCEs produced via free-radical polymerization.
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Affiliation(s)
- Stuart R Berrow
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Richard J Mandle
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Thomas Raistrick
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Matthew Reynolds
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Helen F Gleeson
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
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3
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Rešetič A. Shape programming of liquid crystal elastomers. Commun Chem 2024; 7:56. [PMID: 38485773 PMCID: PMC10940691 DOI: 10.1038/s42004-024-01141-2] [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: 11/27/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
Liquid crystal elastomers (LCEs) are shape-morphing materials that demonstrate reversible actuation when exposed to external stimuli, such as light or heat. The actuation's complexity depends heavily on the instilled liquid crystal alignment, programmed into the material using various shape-programming processes. As an unavoidable part of LCE synthesis, these also introduce geometrical and output restrictions that dictate the final applicability. Considering LCE's future implementation in real-life applications, it is reasonable to explore these limiting factors. This review offers a brief overview of current shape-programming methods in relation to the challenges of employing LCEs as soft, shape-memory components in future devices.
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Affiliation(s)
- Andraž Rešetič
- Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000, Ljubljana, Slovenia.
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4
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Xu Y, Zhang X, Song Z, Chen X, Huang Y, Wang J, Li B, Huang S, Li Q. In situ Light-Writable Orientation Control in Liquid Crystal Elastomer Film Enabled by Chalcones. Angew Chem Int Ed Engl 2024; 63:e202319698. [PMID: 38190301 DOI: 10.1002/anie.202319698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/10/2024]
Abstract
Liquid crystal elastomers (LCEs) are stimulus-responsive materials with intrinsic anisotropy. However, it is still challenging to in situ program the mesogen alignment to realize three-dimensional (3D) deformations with high-resolution patterned structures. This work presents a feasible strategy to program the anisotropy of LCEs by using chalcone mesogens that can undergo a photoinduced cycloaddition reaction under linear polarized light. It is shown that by controlling the polarization director and the irradiation region, patterned alignment distribution in a freestanding LCE film can be created, which leads to complex and reversible 3D shape-morphing behaviors. The work demonstrates an in situ light-writing method to achieve sophisticated topography changes in LCEs, which has potential applications in encryption, sensors, and beyond.
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Affiliation(s)
- Yiyi Xu
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Xinfang Zhang
- Materials Science Graduate Program, Kent State University, Kent, OH-44242, USA
| | - Zhenpeng Song
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Xiao Chen
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Yinliang Huang
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Jinyu Wang
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Bingxiang Li
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Shuai Huang
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Quan Li
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
- Materials Science Graduate Program, Kent State University, Kent, OH-44242, USA
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5
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Feng X, Wang L, Xue Z, Xie C, Han J, Pei Y, Zhang Z, Guo W, Lu B. Melt electrowriting enabled 3D liquid crystal elastomer structures for cross-scale actuators and temperature field sensors. SCIENCE ADVANCES 2024; 10:eadk3854. [PMID: 38446880 PMCID: PMC10917348 DOI: 10.1126/sciadv.adk3854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/30/2024] [Indexed: 03/08/2024]
Abstract
Liquid crystal elastomers (LCEs) have garnered attention for their remarkable reversible strains under various stimuli. Early studies on LCEs mainly focused on basic dimensional changes in macrostructures or quasi-three-dimensional (3D) microstructures. However, fabricating complex 3D microstructures and cross-scale LCE-based structures has remained challenging. In this study, we report a compatible method named melt electrowriting (MEW) to fabricate LCE-based microfiber actuators and various 3D actuators on the micrometer to centimeter scales. By controlling printing parameters, these actuators were fabricated with high resolutions (4.5 to 60 μm), actuation strains (10 to 55%), and a maximum work density of 160 J/kg. In addition, through the integration of a deep learning-based model, we demonstrated the application of LCE materials in temperature field sensing. Large-scale, real-time, LCE grid-based spatial temperature field sensors have been designed, exhibiting a low response time of less than 42 ms and a high precision of 94.79%.
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Affiliation(s)
- Xueming Feng
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
| | - Li Wang
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
- National Innovation Institute of Additive Manufacturing, No. 997, Shanglinyuan 8th Road, Gaoxin District, Xi’an 710300, China
| | - Zhengjie Xue
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
| | - Chao Xie
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
| | - Jie Han
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Yuechen Pei
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
| | - Zhaofa Zhang
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
| | - Wenhua Guo
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
- National Innovation Institute of Additive Manufacturing, No. 997, Shanglinyuan 8th Road, Gaoxin District, Xi’an 710300, China
| | - Bingheng Lu
- The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710054, China
- National Innovation Institute of Additive Manufacturing, No. 997, Shanglinyuan 8th Road, Gaoxin District, Xi’an 710300, China
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6
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Feng F, Dradrach K, Zmyślony M, Barnes M, Biggins JS. Geometry, mechanics and actuation of intrinsically curved folds. SOFT MATTER 2024; 20:2132-2140. [PMID: 38351724 DOI: 10.1039/d3sm01584j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
We combine theory and experiments to explore the kinematics and actuation of intrinsically curved folds (ICFs) in otherwise developable shells. Unlike origami folds, ICFs are not bending isometries of flat sheets, but arise via non-isometric processes (growth/moulding) or by joining sheets along curved boundaries. Experimentally, we implement both, first making joined ICFs from paper, then fabricating flat liquid crystal elastomer (LCE) sheets that morph into ICFs upon heating/swelling via programmed metric changes. Theoretically, an ICF's intrinsic geometry is defined by the geodesic curvatures on either side, κgi. Given these, and a target 3D fold-line, one can construct the entire surface isometrically, and compute the bending energy. This construction shows ICFs are bending mechanisms, with a continuous family of isometries trading fold angle against fold-line curvature. In ICFs with symmetric κgi, straightening the fold-line culminates in a fully-folded flat state that is deployable but weak, while asymmetric ICFs ultimately lock with a mechanically strong finite-angle. When unloaded, freely-hinged ICFs simply adopt the (thickness t independent) isometry that minimizes the bend energy. In contrast, in LCE ICFs a competition between flank and ridge selects a ridge curvature that, unusually, scales as t-1/7. Finally, we demonstrate how multiple ICFs can be combined in one LCE sheet, to create a versatile intrinsically curved gripper that lifts a heavy weight.
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Affiliation(s)
- Fan Feng
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK.
| | - Klaudia Dradrach
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK.
| | - Michał Zmyślony
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK.
| | - Morgan Barnes
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK.
| | - John S Biggins
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK.
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7
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Feng W, He Q, Zhang L. Embedded Physical Intelligence in Liquid Crystalline Polymer Actuators and Robots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312313. [PMID: 38375751 DOI: 10.1002/adma.202312313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/27/2024] [Indexed: 02/21/2024]
Abstract
Responsive materials possess the inherent capacity to autonomously sense and respond to various external stimuli, demonstrating physical intelligence. Among the diverse array of responsive materials, liquid crystalline polymers (LCPs) stand out for their remarkable reversible stimuli-responsive shape-morphing properties and their potential for creating soft robots. While numerous reviews have extensively detailed the progress in developing LCP-based actuators and robots, there exists a need for comprehensive summaries that elucidate the underlying principles governing actuation and how physical intelligence is embedded within these systems. This review provides a comprehensive overview of recent advancements in developing actuators and robots endowed with physical intelligence using LCPs. This review is structured around the stimulus conditions and categorizes the studies involving responsive LCPs based on the fundamental control and stimulation logic and approach. Specifically, three main categories are examined: systems that respond to changing stimuli, those operating under constant stimuli, and those equip with learning and logic control capabilities. Furthermore, the persisting challenges that need to be addressed are outlined and discuss the future avenues of research in this dynamic field.
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Affiliation(s)
- Wei Feng
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Qiguang He
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Zhang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
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8
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den Hoed FM, Carlotti M, Palagi S, Raffa P, Mattoli V. Evolution of the Microrobots: Stimuli-Responsive Materials and Additive Manufacturing Technologies Turn Small Structures into Microscale Robots. MICROMACHINES 2024; 15:275. [PMID: 38399003 PMCID: PMC10893381 DOI: 10.3390/mi15020275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024]
Abstract
The development of functional microsystems and microrobots that have characterized the last decade is the result of a synergistic and effective interaction between the progress of fabrication techniques and the increased availability of smart and responsive materials to be employed in the latter. Functional structures on the microscale have been relevant for a vast plethora of technologies that find application in different sectors including automotive, sensing devices, and consumer electronics, but are now also entering medical clinics. Working on or inside the human body requires increasing complexity and functionality on an ever-smaller scale, which is becoming possible as a result of emerging technology and smart materials over the past decades. In recent years, additive manufacturing has risen to the forefront of this evolution as the most prominent method to fabricate complex 3D structures. In this review, we discuss the rapid 3D manufacturing techniques that have emerged and how they have enabled a great leap in microrobotic applications. The arrival of smart materials with inherent functionalities has propelled microrobots to great complexity and complex applications. We focus on which materials are important for actuation and what the possibilities are for supplying the required energy. Furthermore, we provide an updated view of a new generation of microrobots in terms of both materials and fabrication technology. While two-photon lithography may be the state-of-the-art technology at the moment, in terms of resolution and design freedom, new methods such as two-step are on the horizon. In the more distant future, innovations like molecular motors could make microscale robots redundant and bring about nanofabrication.
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Affiliation(s)
- Frank Marco den Hoed
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, Via R. Piaggio 34, 56025 Pontedera, Italy;
- Smart and Sustainable Polymeric Products, Engineering and Technology Institute Groningen (ENTEG), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands;
| | - Marco Carlotti
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, Via R. Piaggio 34, 56025 Pontedera, Italy;
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via Moruzzi 13, 56124 Pisa, Italy
| | - Stefano Palagi
- BioRobotics Institute, Sant’Anna School of Advanced Studies, P.zza Martiri della Libertà 33, 56127 Pisa, Italy;
| | - Patrizio Raffa
- Smart and Sustainable Polymeric Products, Engineering and Technology Institute Groningen (ENTEG), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands;
| | - Virgilio Mattoli
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, Via R. Piaggio 34, 56025 Pontedera, Italy;
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9
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Yu H, Gold JI, Wolter TJ, Bao N, Smith E, Zhang HA, Twieg RJ, Mavrikakis M, Abbott NL. Actuating Liquid Crystals Rapidly and Reversibly by Using Chemical Catalysis. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2309605. [PMID: 38331028 DOI: 10.1002/adma.202309605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 01/25/2024] [Indexed: 02/10/2024]
Abstract
Microtubules and catalytic motor proteins underlie the microscale actuation of living materials, and they have been used in reconstituted systems to harness chemical energy to drive new states of organization of soft matter (e.g., liquid crystals (LCs)). Such materials, however, are fragile and challenging to translate to technological contexts. Rapid (sub-second) and reversible changes in the orientations of LCs at room temperature using reactions between gaseous hydrogen and oxygen that are catalyzed by Pd/Au surfaces are reported. Surface chemical analysis and computational chemistry studies confirm that dissociative adsorption of H2 on the Pd/Au films reduces preadsorbed O and generates 1 ML of adsorbed H, driving nitrile-containing LCs from a perpendicular to a planar orientation. Subsequent exposure to O2 leads to oxidation of the adsorbed H, reformation of adsorbed O on the Pd/Au surface, and a return of the LC to its initial orientation. The roles of surface composition and reaction kinetics in determining the LC dynamics are described along with a proof-of-concept demonstration of microactuation of beads. These results provide fresh ideas for utilizing chemical energy and catalysis to reversibly actuate functional LCs on the microscale.
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Affiliation(s)
- Huaizhe Yu
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 1 Ho Plaza, Ithaca, NY, 14853, USA
| | - Jake I Gold
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Trenton J Wolter
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Nanqi Bao
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 1 Ho Plaza, Ithaca, NY, 14853, USA
| | - Evangelos Smith
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Hanyu Alice Zhang
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 1 Ho Plaza, Ithaca, NY, 14853, USA
| | - Robert J Twieg
- Department of Chemistry and Biochemistry, Kent State University, 1175 Risman Drive, Kent, OH, 44242, USA
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Nicholas L Abbott
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 1 Ho Plaza, Ithaca, NY, 14853, USA
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10
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Lei B, Wen ZY, Wang HK, Gao J, Chen LJ. Bioinspired Jumping Soft Actuators of the Liquid Crystal Elastomer Enabled by Photo-Mechanical Coupling. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1596-1604. [PMID: 38153381 DOI: 10.1021/acsami.3c16530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Jumping, a fundamental survival behavior observed in organisms, serves as a vital mechanism for adapting to the surrounding environment and overcoming significant obstacles within a given terrain. Here, we present a light-controlled soft jumping actuator inspired by asphondylia, which employs a closed-loop structure and utilizes a liquid crystal elastomer (LCE). Photo-mechanical coupling highlights the significant influence of the light source on the actuator's jumping behavior. Manipulating the light intensity, the relative position of stimulus and light lock, and the concentration of disperse red 1 (DR1) allows precise control over both the maximum take-off velocity and jump height. Furthermore, tailoring the size of the LCE actuator offers a means of regulating jumping behavior. Upon exposure to 460 nm LED irradiation, our actuator achieves remarkable performance, with a maximum jumping height of 10 body length (BL) and take-off velocity of 62 BL/s. These actuators accumulate and rapidly release energy, enabling the effective transportation of microcargos across substantial distances. Our research yields valuable insights into the realm of soft robotics, underscoring the pivotal importance of photo-mechanical coupling in the field of soft robotics, thereby serving as a catalyst for inspiring continued exploration of agile and capable systems by prestoring elastic energy.
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Affiliation(s)
- Bing Lei
- Department of Electronic Engineering, School of Electronic Science and Engineering, Fujian Key Laboratory of Ultrafast Laser Technology and Applications, Xiamen University, Xiamen 361005, China
| | - Zhi-Yuan Wen
- Department of Electronic Engineering, School of Electronic Science and Engineering, Fujian Key Laboratory of Ultrafast Laser Technology and Applications, Xiamen University, Xiamen 361005, China
| | - Hua-Kun Wang
- Department of Civil Engineering, School of Architecture and Civil Engineering, Fujian Key Laboratory of Digital Simulations for Coastal Civil Engineering, Xiamen University, Xiamen 361005, China
| | - Jing Gao
- Department of Civil Engineering, School of Architecture and Civil Engineering, Fujian Key Laboratory of Digital Simulations for Coastal Civil Engineering, Xiamen University, Xiamen 361005, China
| | - Lu-Jian Chen
- Department of Electronic Engineering, School of Electronic Science and Engineering, Fujian Key Laboratory of Ultrafast Laser Technology and Applications, Xiamen University, Xiamen 361005, China
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11
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Mahmood A, Perveen F, Chen S, Akram T, Irfan A. Polymer Composites in 3D/4D Printing: Materials, Advances, and Prospects. Molecules 2024; 29:319. [PMID: 38257232 PMCID: PMC10818632 DOI: 10.3390/molecules29020319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/04/2024] [Accepted: 01/07/2024] [Indexed: 01/24/2024] Open
Abstract
Additive manufacturing (AM), commonly referred to as 3D printing, has revolutionized the manufacturing landscape by enabling the intricate layer-by-layer construction of three-dimensional objects. In contrast to traditional methods relying on molds and tools, AM provides the flexibility to fabricate diverse components directly from digital models without the need for physical alterations to machinery. Four-dimensional printing is a revolutionary extension of 3D printing that introduces the dimension of time, enabling dynamic transformations in printed structures over predetermined periods. This comprehensive review focuses on polymeric materials in 3D printing, exploring their versatile processing capabilities, environmental adaptability, and applications across thermoplastics, thermosetting materials, elastomers, polymer composites, shape memory polymers (SMPs), including liquid crystal elastomer (LCE), and self-healing polymers for 4D printing. This review also examines recent advancements in microvascular and encapsulation self-healing mechanisms, explores the potential of supramolecular polymers, and highlights the latest progress in hybrid printing using polymer-metal and polymer-ceramic composites. Finally, this paper offers insights into potential challenges faced in the additive manufacturing of polymer composites and suggests avenues for future research in this dynamic and rapidly evolving field.
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Affiliation(s)
- Ayyaz Mahmood
- School of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, China;
- School of Life Science and Technology, University of Electronic Science and Technology, Chengdu 610054, China
- School of Art and Design, Guangzhou Panyu Polytechnic, Guangzhou 511483, China
- Dongguan Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, China
| | - Fouzia Perveen
- School of Interdisciplinary Engineering & Sciences (SINES), National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan
| | - Shenggui Chen
- School of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, China;
- School of Art and Design, Guangzhou Panyu Polytechnic, Guangzhou 511483, China
- Dongguan Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, China
| | - Tayyaba Akram
- Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan
| | - Ahmad Irfan
- Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
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12
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Exley T, Hays E, Johnson D, Moridani A, Motati R, Jafari A. Toward a Unified Naming Scheme for Thermo-Active Soft Actuators: A Review of Materials, Working Principles, and Applications. ROBOTICS REPORTS (NEW ROCHELLE, N.Y.) 2024; 2:15-28. [PMID: 38584677 PMCID: PMC10996867 DOI: 10.1089/rorep.2023.0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/12/2023] [Indexed: 04/09/2024]
Abstract
Soft robotics is a rapidly growing field that spans the fields of chemistry, materials science, and engineering. Due to the diverse background of the field, there have been contrasting naming schemes such as "intelligent," "smart," and "adaptive" materials, which add vagueness to the broad innovation among literature. Therefore, a clear, functional, and descriptive naming scheme is proposed in which a previously vague name-Soft Material for Soft Actuators-can remain clear and concise-Phase-Change Elastomers for Artificial Muscles. By synthesizing the working principle, material, and application into a naming scheme, the searchability of soft robotics can be enhanced and applied to other fields. The field of thermo-active soft actuators spans multiple domains and requires added clarity. Thermo-active actuators have potential for a variety of applications spanning virtual reality haptics to assistive devices. This review offers a comprehensive guide to selecting the type of thermo-active actuator when one has an application in mind. In addition, it discusses future directions and improvements that are necessary for implementation.
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Affiliation(s)
- Trevor Exley
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Emilly Hays
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Daniel Johnson
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Arian Moridani
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Ramya Motati
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Amir Jafari
- Advanced Robotic Manipulators (ARM) Lab, the Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
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13
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Becerra D, Xu Y, Wang X, Hall LM. Impact of Molecular-level Structural Disruption on Relaxation Dynamics of Polymers with End-on and Side-on Liquid Crystal Moieties. ACS NANO 2023; 17:24790-24801. [PMID: 38047918 DOI: 10.1021/acsnano.3c05354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
In side-chain liquid crystal polymers (SCLCPs), short side chains are attached on a flexible polymer backbone, and each side chain can have a liquid crystal (LC) group attached at the final bead in either an end-on or a side-on configuration. SCLCPs with random sequences of end-on and side-on LC moieties exhibit nonmonotonic thermal behavior as a function of composition, with some mixed sequences having a lower isotropic to LC phase transition than either purely end-on or side-on configurations. The origin of this nonmonotonic thermal trend lies in the disruption of molecular-level positional ordering and alignment due to the different preferred types of ordering of the different LC attachment types. We compare coarse-grained molecular dynamics (MD) simulations and experiments on SCLCP systems with only one type of LC moiety and demonstrate qualitative agreement in the observed mesophases of end-on and side-on SCLCP systems. Specifically, end-on SCLCPs display a smectic B-like mesophase, with layers of polymer between LC layers, while side-on SCLCPs exhibit a quasi-hexagonal columnar structure of polymer and a nematic surrounding the LC mesophase. Detailed analysis of SCLCP systems with various compositions of these types of LC attachments via MD reveals structural disruption in systems with intermediate compositions. Simulation snapshots and anisotropy ratio measurements show how random SCLCP systems deviate from the expected behavior of prolate or oblate systems in terms of their conformation. This molecular disruption in random SCLCP systems, particularly with a high composition of side-on LC moieties, also significantly impacts the relaxation dynamics. Modifying the composition of the LC type of attachment (molecular structure) is a possible route to tuning both the phase behavior and mechanical response of these systems.
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Affiliation(s)
- Diego Becerra
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yang Xu
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xiaoguang Wang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
- Sustainability Institute, The Ohio State University, Columbus, Ohio 43210, United States
| | - Lisa M Hall
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
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14
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Barnes M, Feng F, Biggins JS. Surface Instability in a Nematic Elastomer. PHYSICAL REVIEW LETTERS 2023; 131:238101. [PMID: 38134776 DOI: 10.1103/physrevlett.131.238101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 11/03/2023] [Indexed: 12/24/2023]
Abstract
Liquid crystal elastomers (LCEs) are soft phase-changing solids that exhibit large reversible contractions upon heating, Goldstone-like soft modes, and resultant microstructural instabilities. We heat a planar LCE slab to isotropic, clamp the lower surface, then cool back to nematic. Clamping prevents macroscopic elongation, producing compression and microstructure. We see that the free surface destabilizes, adopting topography with amplitude and wavelength similar to thickness. To understand the instability, we numerically compute the microstructural relaxation of a "nonideal" LCE energy. Linear stability reveals a Biot-like scale-free instability, but with oblique wave vector. However, simulation and experiment show that, unlike classic elastic creasing, instability culminates in a crosshatch without cusps or hysteresis, and is constructed entirely from low-stress soft modes.
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Affiliation(s)
- Morgan Barnes
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
| | - Fan Feng
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
| | - John S Biggins
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
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15
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Zhang K, Fan Y, Shen S, Yang X, Li T. Tunable Folding Assembly Strategy for Soft Pneumatic Actuators. Soft Robot 2023; 10:1099-1114. [PMID: 37437102 DOI: 10.1089/soro.2022.0166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023] Open
Abstract
With intrinsic compliance, soft pneumatic actuators are widely utilized in delicate tasks. However, complex fabrication approaches and limited tunability are still problems. Here, we propose a tunable folding assembly strategy to design and fabricate soft pneumatic actuators called FASPAs (folding assembly soft pneumatic actuators). A FASPA consists only of a folded silicone tube constrained by rubber bands. By designing local stiffness and folding manner, the FASPA can be designed to achieve four configurations, pure bending, discontinuous-curvature bending, helix, and discontinuous-curvature helix. Analytical models are developed to predict the deformation and the tip trajectory of different configurations. Meanwhile, experiments are performed to verify the models. The stiffness, load capacity, output force, and step response are measured, and fatigue tests are performed. Further, grippers with single, double, and triple fingers are assembled by utilizing different types of FASPAs. As such, objects with different shapes, sizes, and weights can be easily grasped. The folding assembly strategy is a promising method to design and fabricate soft robots with complex configurations to complete tough tasks in harsh environments.
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Affiliation(s)
- Kaihang Zhang
- Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China
- State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou, China
| | - Yaowei Fan
- Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China
- State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou, China
| | - Shiming Shen
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China
- State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou, China
| | - Xuxu Yang
- Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China
- State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou, China
| | - Tiefeng Li
- Center for X-Mechanics, Department of Engineering Mechanics, Zhejiang University, Hangzhou, China
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China
- State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou, China
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16
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Sagnelli D, D’Avino A, Rippa M, Vestri A, Marchesano V, Nenna G, Villani F, Ardila G, Centi S, Ratto F, Petti L. Photomobile Polymer-Piezoelectric Composite for Enhanced Actuation and Energy Generation. ACS APPLIED OPTICAL MATERIALS 2023; 1:1651-1660. [PMID: 37915969 PMCID: PMC10616835 DOI: 10.1021/acsaom.3c00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 11/03/2023]
Abstract
In this study, we present an innovative approach to increase the quantum yield and wavelength sensitivity of photomobile polymer (PMP) films based on azobenzene by doping the polymer matrix with noble metal nanoparticles. These doped PMP films showed faster and more significant bending under both UV as well as visible and near-infrared light regardless of whether it was coherent, incoherent, polarized, or unpolarized irradiation, expanding the potential of PMP-based actuators. To illustrate their practical implications, we created a proof-of-concept model of power generation by coupling it to flexible piezoelectric materials under simulated sunlight. This model has been tested under real operating conditions, thus demonstrating the possibility of generating electricity with variable light exposure. Additionally, our synthetic protocol is solvent-free, which is another benefit of environmental relevance. Our research lays the groundwork for the development of sunlight-sensitive devices, such as photomechanical actuators and advanced photovoltaic modules, which may break ground in the thriving field of smart materials. We are confident that the presented findings will contribute to the ongoing discourse in the field and inspire additional advances in renewable energy applications.
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Affiliation(s)
- Domenico Sagnelli
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
| | - Amalia D’Avino
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
| | - Massimo Rippa
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
| | - Ambra Vestri
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
| | - Valentina Marchesano
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
| | - Giuseppe Nenna
- Energy
and Sustainable Economic Development, ENEA,
Italian National Agency for New Technologies, Portici Research Centre, Portici, Naples 80055, Italy
| | - Fulvia Villani
- Energy
and Sustainable Economic Development, ENEA,
Italian National Agency for New Technologies, Portici Research Centre, Portici, Naples 80055, Italy
| | - Gustavo Ardila
- CNRS,
Grenoble INP, IMEP-LaHC, Univ. Grenoble
Alpes, Univ. Savoie Mont Blanc, Grenoble F-38000, France
| | - Sonia Centi
- Nello
Carrara Institute of Applied Physics of CNR, Sesto Fiorentino 50019, Italy
| | - Fulvio Ratto
- Nello
Carrara Institute of Applied Physics of CNR, Sesto Fiorentino 50019, Italy
| | - Lucia Petti
- Institute
of Applied Sciences and Intelligent Systems of CNR, Pozzuoli 80072, Italy
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17
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Duffy D, McCracken JM, Hebner TS, White TJ, Biggins JS. Lifting, Loading, and Buckling in Conical Shells. PHYSICAL REVIEW LETTERS 2023; 131:148202. [PMID: 37862652 DOI: 10.1103/physrevlett.131.148202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 08/15/2023] [Indexed: 10/22/2023]
Abstract
Liquid crystal elastomer films that morph into cones are strikingly capable lifters. Thus motivated, we combine theory, numerics, and experiments to reexamine the load-bearing capacity of conical shells. We show that a cone squashed between frictionless surfaces buckles at a smaller load, even in scaling, than the classical Seide-Koiter result. Such buckling begins in a region of greatly amplified azimuthal compression generated in an outer boundary layer with oscillatory bend. Experimentally and numerically, buckling then grows subcritically over the full cone. We derive a new thin-limit formula for the critical load, ∝t^{5/2}, and validate it numerically. We also investigate deep postbuckling, finding further instabilities producing intricate states with multiple Pogorelov-type curved ridges arranged in concentric circles or Archimedean spirals. Finally, we investigate the forces exerted by such states, which limit lifting performance in active cones.
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Affiliation(s)
- Daniel Duffy
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
| | - Joselle M McCracken
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, USA
| | - Tayler S Hebner
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, USA
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, USA
| | - John S Biggins
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
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18
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Wang Q, Tian X, Zhang D, Zhou Y, Yan W, Li D. Programmable spatial deformation by controllable off-center freestanding 4D printing of continuous fiber reinforced liquid crystal elastomer composites. Nat Commun 2023; 14:3869. [PMID: 37391425 DOI: 10.1038/s41467-023-39566-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 06/16/2023] [Indexed: 07/02/2023] Open
Abstract
Owing to their high deformation ability, 4D printed structures have various applications in origami structures, soft robotics and deployable mechanisms. As a material with programmable molecular chain orientation, liquid crystal elastomer is expected to produce the freestanding, bearable and deformable three-dimensional structure. However, majority of the existing 4D printing methods for liquid crystal elastomers can only fabricate planar structures, which limits their deformation designability and bearing capacity. Here we propose a direct ink writing based 4D printing method for freestanding continuous fiber reinforced composites. Continuous fibers can support freestanding structures during the printing process and improve the mechanical property and deformation ability of 4D printed structures. In this paper, the integration of 4D printed structures with fully impregnated composite interfaces, programmable deformation ability and high bearing capacity are realized by adjusting the off-center distribution of the fibers, and the printed liquid crystal composite can carry a load of up to 2805 times its own weight and achieve a bending deformation curvature of 0.33 mm-1 at 150 °C. This research is expected to open new avenues for creating soft robotics, mechanical metamaterials and artificial muscles.
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Affiliation(s)
- Qingrui Wang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China
| | - Xiaoyong Tian
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China.
| | - Daokang Zhang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China
| | - Yanli Zhou
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China
| | - Wanquan Yan
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China
| | - Dichen Li
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China
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19
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Chen M, Gao M, Bai L, Zheng H, Qi HJ, Zhou K. Recent Advances in 4D Printing of Liquid Crystal Elastomers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209566. [PMID: 36461147 DOI: 10.1002/adma.202209566] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/22/2022] [Indexed: 06/09/2023]
Abstract
Liquid crystal elastomers (LCEs) are renowned for their large, reversible, and anisotropic shape change in response to various external stimuli due to their lightly cross-linked polymer networks with an oriented mesogen direction, thus showing great potential for applications in robotics, bio-medics, electronics, optics, and energy. To fully take advantage of the anisotropic stimuli-responsive behaviors of LCEs, it is preferable to achieve a locally controlled mesogen alignment into monodomain orientations. In recent years, the application of 4D printing to LCEs opens new doors for simultaneously programming the mesogen alignment and the 3D geometry, offering more opportunities and higher feasibility for the fabrication of 4D-printed LCE objects with desirable stimuli-responsive properties. Here, the state-of-the-art advances in 4D printing of LCEs are reviewed, with emphasis on both the mechanisms and potential applications. First, the fundamental properties of LCEs and the working principles of the representative 4D printing techniques are briefly introduced. Then, the fabrication of LCEs by 4D printing techniques and the advantages over conventional manufacturing methods are demonstrated. Finally, perspectives on the current challenges and potential development trends toward the 4D printing of LCEs are discussed, which may shed light on future research directions in this new field.
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Affiliation(s)
- Mei Chen
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Ming Gao
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Lichun Bai
- School of Traffic and Transportation Engineering, Central South University, Changsha, 410075, China
| | - Han Zheng
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - H Jerry Qi
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Kun Zhou
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
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20
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Dradrach K, Zmyślony M, Deng Z, Priimagi A, Biggins J, Wasylczyk P. Light-driven peristaltic pumping by an actuating splay-bend strip. Nat Commun 2023; 14:1877. [PMID: 37015926 PMCID: PMC10073117 DOI: 10.1038/s41467-023-37445-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/15/2023] [Indexed: 04/06/2023] Open
Abstract
Despite spectacular progress in microfluidics, small-scale liquid manipulation, with few exceptions, is still driven by external pumps and controlled by large-scale valves, increasing cost and size and limiting complexity. By contrast, optofluidics uses light to power, control and monitor liquid manipulation, potentially allowing for small, self-contained microfluidic devices. Here we demonstrate a soft light-propelled actuator made of liquid crystal gel that pumps microlitre volumes of water. The strip of actuating material serves as both a pump and a channel leading to an extremely simple microfluidic architecture that is both powered and controlled by light. The performance of the pump is well explained by a simple theoretical model in which the light-induced bending of the actuator competes with the liquid's surface tension. The theory highlights that effective pumping requires a threshold light intensity and strip width. The proposed system explores the benefits of shifting the complexity of microfluidic systems from the fabricated device to spatio-temporal control over stimulating light patterns.
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Affiliation(s)
- Klaudia Dradrach
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
- Faculty of Physics, University of Warsaw, Warsaw, Poland.
| | - Michał Zmyślony
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Zixuan Deng
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Arri Priimagi
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - John Biggins
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
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21
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Peng M, Zhao Q, Wang M, Du X. Reconfigurable scaffolds for adaptive tissue regeneration. NANOSCALE 2023; 15:6105-6120. [PMID: 36919563 DOI: 10.1039/d3nr00281k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Tissue engineering and regenerative medicine have offered promising alternatives for clinical treatment of body tissue traumas, losses, dysfunctions, or diseases, where scaffold-based strategies are particularly popular and effective. Over the decades, scaffolds for tissue regeneration have been remarkably evolving. Nevertheless, conventional scaffolds still confront grand challenges in bio-adaptions in terms of both tissue-scaffold and cell-scaffold interplays, for example complying with complicated three-dimensional (3D) shapes of biological tissues and recapitulating the ordered cell regulation effects of native cell microenvironments. Benefiting from the recent advances in "intelligent" biomaterials, reconfigurable scaffolds have been emerging, demonstrating great promise in addressing the bio-adaption challenges through altering their macro-shapes and/or micro-structures. This mini-review article presents a brief overview of the cutting-edge research on reconfigurable scaffolds, summarizing the materials for forming reconfigurable scaffolds and highlighting their applications for adaptive tissue regeneration. Finally, the challenges and prospects of reconfigurable scaffolds are also discussed, shedding light on the bright future of next-generation reconfigurable scaffolds with upgrading adaptability.
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Affiliation(s)
- Mingxing Peng
- Institute of Biomedical & Health Engineering, Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, 518055, China.
- University of Chinese Academy of Sciences, China
| | - Qilong Zhao
- Institute of Biomedical & Health Engineering, Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, 518055, China.
| | - Min Wang
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Xuemin Du
- Institute of Biomedical & Health Engineering, Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, 518055, China.
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22
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Liang H, Wei Y, Ji Y. Magnetic-responsive Covalent Adaptable Networks. Chem Asian J 2023; 18:e202201177. [PMID: 36645376 DOI: 10.1002/asia.202201177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/07/2023] [Accepted: 01/16/2023] [Indexed: 01/17/2023]
Abstract
Covalent adaptable networks (CANs) are reprocessable polymers whose structural arrangement is based on the recombination of dynamic covalent bonds. Composite materials prepared by incorporating magnetic particles into CANs attract much attention due to their remote and precise control, fast response speed, high biological safety and strong penetration of magnetic stimuli. These properties often involve magnetothermal effect and direct magnetic-field guidance. Besides, some of them can also respond to light, electricity or pH values. Thus, they are favorable for soft actuators since various functions are achieved such as magnetic-assisted self-healing (heating or at ambient temperature), welding (on land or under water), shape-morphing, and so on. Although magnetic CANs just start to be studied in recent two years, their advances are promised to expand the practical applications in both cutting-edge academic and engineering fields. This review aims to summarize recent progress in magnetic-responsive CANs, including their design, synthesis and application.
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Affiliation(s)
- Huan Liang
- The Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yen Wei
- The Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.,Department of Chemistry, Center for Nanotechnology and Institute of Biomedical Technology, Chung-Yuan Christian University Chung-Li, 32023, Taiwan, P. R. China
| | - Yan Ji
- The Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
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23
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Hebner TS, Bowman RGA, Duffy D, Mostajeran C, Griniasty I, Cohen I, Warner M, Bowman CN, White TJ. Discontinuous Metric Programming in Liquid Crystalline Elastomers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:11092-11098. [PMID: 36791283 DOI: 10.1021/acsami.2c21984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Liquid crystalline elastomers (LCEs) are shape-changing materials that exhibit large deformations in response to applied stimuli. Local control of the orientation of LCEs spatially directs the deformation of these materials to realize a spontaneous shape change in response to stimuli. Prior approaches to shape programming in LCEs utilize patterning techniques that involve the detailed inscription of spatially varying nematic fields to produce sheets. These patterned sheets deform into elaborate geometries with complex Gaussian curvatures. Here, we present an alternative approach to realize shape-morphing in LCEs where spatial patterning of the crosslink density locally regulates the material deformation magnitude on either side of a prescribed interface curve. We also present a simple mathematical model describing the behavior of these materials. Further experiments coupled with the mathematical model demonstrate the control of the sign of Gaussian curvature, which is used in combination with heat transfer effects to design LCEs that self-clean as a result of temperature-dependent actuation properties.
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Affiliation(s)
- Tayler S Hebner
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States
| | - Riley G A Bowman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States
| | - Daniel Duffy
- Department of Engineering, University of Cambridge, Cambridge, England CB2 1PZ, U.K
| | - Cyrus Mostajeran
- Department of Engineering, University of Cambridge, Cambridge, England CB2 1PZ, U.K
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Itay Griniasty
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501, United States
| | - Itai Cohen
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501, United States
| | - Mark Warner
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Christopher N Bowman
- 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, 596 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, 596 UCB, Boulder, Colorado 80309, United States
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24
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Najiya N, Popov N, Jampani VSR, Lagerwall JPF. Continuous Flow Microfluidic Production of Arbitrarily Long Tubular Liquid Crystal Elastomer Peristaltic Pump Actuators. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2204693. [PMID: 36494179 DOI: 10.1002/smll.202204693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/14/2022] [Indexed: 06/17/2023]
Abstract
While liquid crystal elastomers (LCEs) are ideal materials for soft-robotic actuators, filling the role of muscle and shape-defining material simultaneously, it is non-trivial to give them ground state shapes beyond simple sheets or fibers. Here tubular LCE actuators scalable to arbitrary length are produced using a continuous three-phase coaxial flow microfluidic process. By pumping an oligomeric precursor solution between inner and outer aqueous phases in a cylindrically symmetric nested capillary set-up, and by reducing the interfacial tension to negligible values using surfactants adapted to each phase, the tubular liquid flow is stabilized over distances more than 200 times the diameter or 2000 times the thickness. In situ photocrosslinking of the middle phase turns it into an LCE network that is flow-aligned by the shear gradient over the phase. The reversible actuation of the tubes upon heating yields a reduction of the interior space, pumping out enclosed fluid, and the relaxation upon cooling leads to the fluid being sucked back in. By moving a local heat source along the tube, it acts as a peristaltic pump. It is proposed that the tubes could, pending functionalization for light-triggered actuation, function as active synthetic vasculature in biological contexts.
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Affiliation(s)
- Najiya Najiya
- Department of Physics and Materials Science, University of Luxembourg, 162a avenue de la faiencerie, Luxembourg city, 1511, Luxembourg
| | - Nikolay Popov
- Department of Physics and Materials Science, University of Luxembourg, 162a avenue de la faiencerie, Luxembourg city, 1511, Luxembourg
| | - Venkata Subba Rao Jampani
- Department of Physics and Materials Science, University of Luxembourg, 162a avenue de la faiencerie, Luxembourg city, 1511, Luxembourg
- Department of Condensed Matter Physics, Jozef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Jan P F Lagerwall
- Department of Physics and Materials Science, University of Luxembourg, 162a avenue de la faiencerie, Luxembourg city, 1511, Luxembourg
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25
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Yasuoka H, Takahashi KZ, Aoyagi T. Impact of molecular architectures on mesogen reorientation relaxation and post-relaxation stress of liquid crystal elastomers under electric fields. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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26
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Hebner TS, Korner K, Bowman CN, Bhattacharya K, White TJ. Leaping liquid crystal elastomers. SCIENCE ADVANCES 2023; 9:eade1320. [PMID: 36652507 PMCID: PMC9848472 DOI: 10.1126/sciadv.ade1320] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Snap-through mechanisms are pervasive in everyday life in biological systems, engineered devices, and consumer products. Snap-through transitions can be realized in responsive materials via stimuli-induced mechanical instability. Here, we demonstrate a rapid and powerful snap-through response in liquid crystalline elastomers (LCEs). While LCEs have been extensively examined as material actuators, their deformation rate is limited by the second-order character of their phase transition. In this work, we locally pattern the director orientation of LCEs and fabricate mechanical elements with through-thickness (functionally graded) modulus gradients to realize stimuli-induced responses as fast as 6 ms. The rapid acceleration and associated force output of the LCE elements cause the elements to leap to heights over 200 times the material thickness. The experimental examination in functionally graded LCE elements is complemented with computational evaluation of the underlying mechanics. The experimentally validated model is then exercised as a design tool to guide functional implementation, visualized as directional leaping.
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Affiliation(s)
- Tayler S. Hebner
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Kevin Korner
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christopher N. Bowman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Kaushik Bhattacharya
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
| | - Timothy J. White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO 80309, USA
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27
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Guillen Campos J, Stricker F, Clark KD, Park M, Bailey SJ, Kuenstler AS, Hayward RC, Read de Alaniz J. Controlled Diels-Alder "Click" Strategy to Access Mechanically Aligned Main-Chain Liquid Crystal Networks. Angew Chem Int Ed Engl 2023; 62:e202214339. [PMID: 36315038 DOI: 10.1002/anie.202214339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Indexed: 12/05/2022]
Abstract
Aligned liquid crystal polymers are materials of interest for electronic, optic, biological and soft robotic applications. The manufacturing and processing of these materials have been widely explored with mechanical alignment establishing itself as a preferred method due to its ease of use and widespread applicability. However, the fundamental chemistry behind the required two-step polymerization for mechanical alignment has limitations in both fabrication and substrate compatibility. In this work we introduce a new protection-deprotection approach utilizing a two-stage Diels-Alder cyclopentadiene-maleimide step-growth polymerization to enable mild yet efficient, fast, controlled, reproducible and user-friendly polymerizations, broadening the scope of liquid crystal systems. Thorough characterization of the films by DSC, DMA, POM and WAXD show the successful synthesis of a uniaxially aligned liquid crystal network with thermomechanical actuation abilities.
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Affiliation(s)
- Jesus Guillen Campos
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Friedrich Stricker
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Kyle D Clark
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Minwook Park
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Sophia J Bailey
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Alexa S Kuenstler
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Ryan C Hayward
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80305, USA
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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28
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Brighenti R, Cosma MP. Multiphysics modelling of light-actuated liquid crystal elastomers. Proc Math Phys Eng Sci 2023. [DOI: 10.1098/rspa.2022.0417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Liquid crystalline elastomers (LCEs) represent a promising class of responsive polymers whose physical properties are peculiar to both fluids and solids. Thanks to their microscale structure made of elongated rigid molecules (mesogens)—characterized by their capability to reversibly switch from an isotropic to an ordered state—LCEs exhibit a number of remarkable physical effects, such as self-deformation and mechanical actuation triggered by external stimuli. Efficient and physics-based modelling, aimed at designing and optimizing LCE-based devices (such as artificial muscles, deployable structures, soft actuators, etc.), is a fundamental tool to quantitatively describe their mechanical behaviour in real applications. In the present study, we illustrate the multi-physics modelling of light-driven deformation of LCEs, based on the photo-thermal energy conversion. The role played by the light diffusion and heat transfer within the medium is considered and their effect on the obtainable actuation is studied through numerical simulations based on the multi-physics theory developed.
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Affiliation(s)
- Roberto Brighenti
- Department of Engineering and Architecture, University of Parma, Viale delle Scienze 181/A, 43124 Parma, Italy
| | - Mattia P. Cosma
- Department of Engineering and Architecture, University of Parma, Viale delle Scienze 181/A, 43124 Parma, Italy
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29
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Sentjens H, Kragt AJ, Lub J, Claessen MD, Buurman VE, Schreppers J, Gongriep HA, Schenning AP. Programming Thermochromic Liquid Crystal Hetero-Oligomers for Near-Infrared Reflectors: Unequal Incorporation of Similar Reactive Mesogens in Thiol-ene Oligomers. Macromolecules 2022; 56:59-68. [PMID: 36644552 PMCID: PMC9835980 DOI: 10.1021/acs.macromol.2c02041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/15/2022] [Indexed: 12/28/2022]
Abstract
Cholesteric liquid crystal oligomers are widely researched for their interesting thermochromic properties. However, structure-property relationships to program the thermochromic properties of these oligomers have been rarely reported. In this work, we use the versatile thiol-ene click reaction to synthesize a series of hetero-oligomers and study the impact of different compositions on the thermochromic behavior of the resulting material. Characterization of the oligomers shows significantly different rates of reaction for the monomers despite their very similar structures, which leads to oligomer compositions that do not match the original reaction feed. The oligomers are then used to produce thin near-infrared reflecting coatings. The best-performing thermochromic reflector has a room-temperature reflection band that shifts a total of 510 nanometers upon heating to 120 °C. The shift is repeatable for up to 10 times with no appreciable degradation. The room temperature reflection of the coatings is shown to be tunable not only by adjusting the chiral dopant concentration but also by the ratio of the monomers. Finally, we show that the oligomers can be chemically modified by making their reactive end groups undergo a reaction with monothiol compounds. These modifications allow for further fine-tuning of liquid crystal oligomers for heat-regulating window films, for example.
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Affiliation(s)
- Henk Sentjens
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands,Institute
for Complex Molecular Systems, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Augustinus J.J. Kragt
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands,Faculty
of Architecture, Delft University of Technology, Julianalaan 134, 2628 BLDelft, The Netherlands,ClimAd
Technology, Valkenaerhof
68, 6538 TENijmegen, The Netherlands
| | - Johan Lub
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Mart D.T. Claessen
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Vera E. Buurman
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Joris Schreppers
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Henk A. Gongriep
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands
| | - Albert P.H.J. Schenning
- Laboratory
of Stimuli-Responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands,Institute
for Complex Molecular Systems, Eindhoven
University of Technology (TU/e), P.O. Box 513, 5600 MBEindhoven, The Netherlands,
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30
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Regression analysis for predicting the elasticity of liquid crystal elastomers. Sci Rep 2022; 12:19788. [PMID: 36396780 PMCID: PMC9672114 DOI: 10.1038/s41598-022-23897-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022] Open
Abstract
It is highly desirable but difficult to understand how microscopic molecular details influence the macroscopic material properties, especially for soft materials with complex molecular architectures. In this study we focus on liquid crystal elastomers (LCEs) and aim at identifying the design variables of their molecular architectures that govern their macroscopic deformations. We apply the regression analysis using machine learning (ML) to a database containing the results of coarse grained molecular dynamics simulations of LCEs with various molecular architectures. The predictive performance of a surrogate model generated by the regression analysis is also tested. The database contains design variables for LCE molecular architectures, system and simulation conditions, and stress-strain curves for each LCE molecular system. Regression analysis is applied using the stress-strain curves as objective variables and the other factors as explanatory variables. The results reveal several descriptors governing the stress-strain curves. To test the predictive performance of the surrogate model, stress-strain curves are predicted for LCE molecular architectures that were not used in the ML scheme. The predicted curves capture the characteristics of the results obtained from molecular dynamics simulations. Therefore, the ML scheme has great potential to accelerate LCE material exploration by detecting the key design variables in the molecular architecture and predicting the LCE deformations.
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31
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Kim IH, Choi S, Lee J, Jung J, Yeo J, Kim JT, Ryu S, Ahn SK, Kang J, Poulin P, Kim SO. Human-muscle-inspired single fibre actuator with reversible percolation. NATURE NANOTECHNOLOGY 2022; 17:1198-1205. [PMID: 36302962 PMCID: PMC9646516 DOI: 10.1038/s41565-022-01220-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 08/22/2022] [Indexed: 05/19/2023]
Abstract
Artificial muscles are indispensable components for next-generation robotics capable of mimicking sophisticated movements of living systems. However, an optimal combination of actuation parameters, including strain, stress, energy density and high mechanical strength, is required for their practical applications. Here we report mammalian-skeletal-muscle-inspired single fibres and bundles with large and strong contractive actuation. The use of exfoliated graphene fillers within a uniaxial liquid crystalline matrix enables photothermal actuation with large work capacity and rapid response. Moreover, the reversible percolation of graphene fillers induced by the thermodynamic conformational transition of mesoscale structures can be in situ monitored by electrical switching. Such a dynamic percolation behaviour effectively strengthens the mechanical properties of the actuator fibres, particularly in the contracted actuation state, enabling mammalian-muscle-like reliable reversible actuation. Taking advantage of a mechanically compliant fibre structure, smart actuators are readily integrated into strong bundles as well as high-power soft robotics with light-driven remote control.
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Affiliation(s)
- In Ho Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- National Creative Research Initiative Center for Multi-dimensional Directed Nanoscale Assembly, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Subi Choi
- Department of Polymer Science and Engineering, Pusan National University, Busan, Republic of Korea
| | - Jieun Lee
- Department of Polymer Science and Engineering, Pusan National University, Busan, Republic of Korea
| | - Jiyoung Jung
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jinwook Yeo
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jun Tae Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- National Creative Research Initiative Center for Multi-dimensional Directed Nanoscale Assembly, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Seunghwa Ryu
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Suk-Kyun Ahn
- Department of Polymer Science and Engineering, Pusan National University, Busan, Republic of Korea
| | - Jiheong Kang
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Philippe Poulin
- Université de Bordeaux, CNRS, Centre de Recherche Paul Pascal, Pessac, France
| | - Sang Ouk Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
- National Creative Research Initiative Center for Multi-dimensional Directed Nanoscale Assembly, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
- Materials Creation, Seoul, Republic of Korea.
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32
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Yan H, He Y, Yao L, Wang X, Zhang X, Zhang Y, Han D, Li C, Sun L, Zhang J. Thermo-crosslinking assisted preparation of thiol-acrylate main-chain liquid-crystalline elastomers. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-022-03238-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Li Y, Teixeira Y, Parlato G, Grace J, Wang F, Huey BD, Wang X. Three-dimensional thermochromic liquid crystal elastomer structures with reversible shape-morphing and color-changing capabilities for soft robotics. SOFT MATTER 2022; 18:6857-6867. [PMID: 36043504 DOI: 10.1039/d2sm00876a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Functional structures with reversible shape-morphing and color-changing capabilities are promising for applications including soft robotics and biomimetic camouflage devices. Despite extensive studies, there are few reports on achieving both reversible shape-switching and color-changing capabilities within one structure. Here, we report a facile and versatile strategy to realize such capabilities via spatially programmed liquid crystal elastomer (LCE) structures incorporated with thermochromic dyes. By coupling the shape-changing behavior of LCEs resulting from the nematic-to-isotropic transition of liquid crystals with the color-changing thermochromic dyes, 3D thermochromic LCE structures change their shapes and colors simultaneously, which are controlled by the nematic-isotropic transition temperature of LCEs and the critical color-changing temperature of dyes, respectively. Demonstrations, including the simulated blooming process of a resembled flower, the camouflage behavior of a "butterfly"/"chameleon" robot in response to environmental changes, and the underwater camouflage of an "octopus" robot, highlight the reliability of this strategy. Furthermore, integrating micro-ferromagnetic particles into the "octopus" thermochromic LCE robot allows it to respond to thermal-magnetic dual stimuli for "adaptive" motion and diverse biomimetic motion modes, including swimming, rolling, rotating, and crawling, accompanied by color-changing behaviors for camouflage. The reversibly reconfigurable and color-changing thermochromic LCE structures are promising for applications including soft camouflage robots and multifunctional biomimetic devices.
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Affiliation(s)
- Yi Li
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Yasmin Teixeira
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA
| | - Gina Parlato
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Jaclyn Grace
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Fei Wang
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Bryan D Huey
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Xueju Wang
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA.
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34
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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: 3] [Impact Index Per Article: 1.5] [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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35
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Ohzono T, Koyama E. Enhanced photocontrollable dynamic adhesion of nematic elastomers on rough surfaces. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Ohzono T, Koyama E. Photo-Rewritable Glaring Patterns Composed of Stripe Domains in Nematic Elastomers. Macromol Rapid Commun 2022; 43:e2200599. [PMID: 35904150 DOI: 10.1002/marc.202200599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/21/2022] [Indexed: 11/08/2022]
Abstract
Dynamic ordered micropatterns in polymeric materials provide an effective approach for the on-demand tuning of optical properties toward a smart optical material. In this study, we show that glaring patterns exhibiting strong anisotropic light diffusion can be developed at specific locations in nematic liquid-crystal elastomers with light-sensitive azobenzene units. Glaring originates from the stripe domains of the nematic directors that self-organize in light-irradiated regions after a simple uniaxial stretching and releasing process without any complicated lithographic technique. The nematic order transiently reduced by the photo-induced cis azobenzene isomers unlocks entropic elasticity, which induces local uniaxial shrinkage that causes buckling of the directors forming stripe domains. The written pattern on the film is tangibly visible with the backlight owing to the difference in anisotropic light diffusion. Furthermore, this pattern can be erased by light irradiation or thermal annealing. These films can be applied to optical elements for achieving augmented luminaries, security labeling, and sign-sheeting applications. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Takuya Ohzono
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565, Japan
| | - Emiko Koyama
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8565, Japan
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37
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Photothermal-Driven Liquid Crystal Elastomers: Materials, Alignment and Applications. Molecules 2022; 27:molecules27144330. [PMID: 35889204 PMCID: PMC9317631 DOI: 10.3390/molecules27144330] [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: 06/15/2022] [Revised: 07/02/2022] [Accepted: 07/04/2022] [Indexed: 02/01/2023] Open
Abstract
Liquid crystal elastomers (LCEs) are programmable deformable materials that can respond to physical fields such as light, heat, and electricity. Photothermal-driven LCE has the advantages of accuracy and remote control and avoids the requirement of high photon energy for photochemistry. In this review, we discuss recent advances in photothermal LCE materials and investigate methods for mechanical alignment, external field alignment, and surface-induced alignment. Advances in the synthesis and orientation of LCEs have enabled liquid crystal elastomers to meet applications in optics, robotics, and more. The review concludes with a discussion of current challenges and research opportunities.
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38
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Xiao YY, Jiang ZC, Hou JB, Chen XS, Zhao Y. Electrically driven liquid crystal network actuators. SOFT MATTER 2022; 18:4850-4867. [PMID: 35730498 DOI: 10.1039/d2sm00544a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Soft actuators based on liquid crystal networks (LCNs) have aroused great scientific interest for use as stimuli-controlled shape-changing and moving components for robotic devices due to their fast, large, programmable and solvent-free actuation responses. Recently, various LCN actuators have been implemented in soft robotics using stimulus sources such as heat, light, humidity and chemical reactions. Among them, electrically driven LCN actuators allow easy modulation and programming of the input electrical signals (amplitude, phase, and frequency) as well as stimulation throughout the volume, rendering them promising actuators for practical applications. Herein, the progress of electrically driven LCN actuators regarding their construction, actuation mechanisms, actuation performance, actuation programmability and the design strategies for intelligent systems is elucidated. We also discuss new robotic functions and advanced actuation control. Finally, an outlook is provided, highlighting the research challenges faced with this type of actuator.
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Affiliation(s)
- Yao-Yu Xiao
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Zhi-Chao Jiang
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Jun-Bo Hou
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Xin-Shi Chen
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - Yue Zhao
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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39
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Chen Y, Kuenstler AS, Hayward RC, Jin L. Formation of rolls from liquid crystal elastomer bistrips. SOFT MATTER 2022; 18:4077-4089. [PMID: 35603603 DOI: 10.1039/d1sm01830b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Formation of desired three-dimensional (3D) shapes from flat thin sheets with programmed non-uniform deformation profiles is an effective strategy to create functional 3D structures. Liquid crystal elastomers (LCEs) are of particular use in programmable shape morphing due to their ability to undergo large, reversible, and anisotropic deformation in response to a stimulus. Here we consider a rectangular monodomain LCE thin sheet divided into one high- and one low-temperature strip, which we dub a 'bistrip'. Upon activation, a discontinuously patterned, anisotropic in-plane stretch profile is generated, and induces buckling of the bistrip into a rolled shape with a transitional bottle neck. Based on the non-Euclidean plate theory, we derive an analytical model to quantitatively capture the formation of the rolled shapes from a flat bistrip with finite thickness by minimizing the total elastic energy involving both stretching and bending energies. Using this analytical model, we identify the critical thickness at which the transition from the unbuckled to buckled configuration occurs. We further study the influence of the anisotropy of the stretch profile on the rolled shapes by first converting prescribed metric tensors with different anisotropy to a unified metric tensor embedded in a bistrip of modified geometry, and then investigating the effect of each parameter in this unified metric tensor on the rolled shapes. Our analysis sheds light on designing shape morphing of LCE thin sheets, and provides quantitative predictions on the 3D shapes that programmed LCE sheets can form upon activation for various applications.
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Affiliation(s)
- Yuzhen Chen
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA.
| | - Alexa S Kuenstler
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80309, USA.
| | - Ryan C Hayward
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80309, USA.
| | - Lihua Jin
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA.
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40
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Feng F, Duffy D, Warner M, Biggins JS. Interfacial metric mechanics: stitching patterns of shape change in active sheets. Proc Math Phys Eng Sci 2022; 478:20220230. [PMID: 35814332 PMCID: PMC9240917 DOI: 10.1098/rspa.2022.0230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/09/2022] [Indexed: 11/22/2022] Open
Abstract
A flat sheet programmed with a planar pattern of spontaneous shape change will morph into a curved surface. Such metric mechanics is seen in growing biological sheets, and may be engineered in actuating soft matter sheets such as phase-changing liquid crystal elastomers (LCEs), swelling gels and inflating baromorphs. Here, we show how to combine multiple patterns in a sheet by stitching regions of different shape changes together piecewise along interfaces. This approach allows simple patterns to be used as building blocks, and enables the design of multi-material or active/passive sheets. We give a general condition for an interface to be geometrically compatible, and explore its consequences for LCE/LCE, gel/gel and active/passive interfaces. In contraction/elongation systems such as LCEs, we find an infinite set of compatible interfaces between any pair of patterns along which the metric is discontinuous, and a finite number across which the metric is continuous. As an example, we find all possible interfaces between pairs of LCE logarithmic spiral patterns. By contrast, in isotropic systems such as swelling gels, only a finite number of continuous interfaces are available, greatly limiting the potential of stitching. In both continuous and discontinuous cases, we find the stitched interfaces generically carry singular Gaussian curvature, leading to intrinsically curved folds in the actuated surface. We give a general expression for the distribution of this curvature, and a more specialized form for interfaces in LCE patterns. The interfaces thus also have rich geometric and mechanical properties in their own right.
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Affiliation(s)
- Fan Feng
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Daniel Duffy
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Mark Warner
- Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
| | - John S. Biggins
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
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41
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Bauman GE, Koch JA, White TJ. Rheology of liquid crystalline oligomers for 3-D printing of liquid crystalline elastomers. SOFT MATTER 2022; 18:3168-3176. [PMID: 35380153 DOI: 10.1039/d2sm00166g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Liquid crystalline monomers can be oligomerized and subsequently 3-D printed to prepare liquid crystalline elastomers (LCEs) with spatial variation of the nematic director to create soft materials that undergo complex shape change when subject to stimulus. Here, we detail the correlation of alignment in 3-D printed LCE on the shear history of the oligomeric ink. This coupling is evident both in the polymerization of sheared LCE samples as well as steady-state rheological experiments that quantify the time-dependent flow behaviors of these complex fluids. Under a steady shear flow, oligomeric LC inks transition from a nematic state with unaligned (polydomain) orientation to a uniaxially aligned (monodomain) nematic phase over a large range of applied strain. After cessation of shear flow, the oligomeric LC inks return the polydomain orientation over approximately 30 minutes. The alignment of liquid crystalline segments in the LCE (and the associated stimuli-response of the materials) is ultimately correlated to the degree of strain applied to the ink.
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Affiliation(s)
- Grant E Bauman
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, 80309, USA.
| | - Jeremy A Koch
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, 80309, USA.
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, 80309, USA.
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42
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Yasuoka H, Takahashi KZ, Aoyagi T. Trade-off effect between the stress and strain range in the soft elasticity of liquid crystalline elastomers. Polym J 2022. [DOI: 10.1038/s41428-022-00641-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Li Y, Liu T, Ambrogi V, Rios O, Xia M, He W, Yang Z. Liquid Crystalline Elastomers Based on Click Chemistry. ACS APPLIED MATERIALS & INTERFACES 2022; 14:14842-14858. [PMID: 35319184 DOI: 10.1021/acsami.1c21096] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Liquid crystalline elastomers (LCEs) have emerged as an important class of functional materials that are suitable for a wide range of applications, such as sensors, actuators, and soft robotics. The unique properties of LCEs originate from the combination between liquid crystal and elastomeric network. The control of macroscopic liquid crystalline orientation and network structure is crucial to realizing the useful functionalities of LCEs. A variety of chemistries have been developed to fabricate LCEs, including hydrosilylation, free radical polymerization of acrylate, and polyaddition of epoxy and carboxylic acid. Over the past few years, the use of click chemistry has become a more robust and energy-efficient way to construct LCEs with desired structures. This article provides an overview of emerging LCEs based on click chemistries, including aza-Michael addition between amine and acrylate, radical-mediated thiol-ene and thiol-yne reactions, base-catalyzed thiol-acrylate and thiol-epoxy reactions, copper-catalyzed azide-alkyne cycloaddition, and Diels-Alder cycloaddition. The similarities and differences of these reactions are discussed, with particular attention focused on the strengths and limitations of each reaction for the preparation of LCEs with controlled structures and orientations. The compatibility of these reactions with the traditional and emerging processing techniques, such as surface alignment and additive manufacturing, are surveyed. Finally, the challenges and opportunities of using click chemistry for the design of LCEs with advanced functionalities and applications are discussed.
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Affiliation(s)
- Yuzhan Li
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Tuan Liu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Veronica Ambrogi
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Napoli 80125, Italy
| | - Orlando Rios
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Min Xia
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Wanli He
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhou Yang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
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44
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Yu Z, Shang J, Shi Q, Xia Y, Zhai DH, Wang H, Huang Q, Fukuda T. Electrically Controlled Aquatic Soft Actuators with Desynchronized Actuation and Light-Mediated Reciprocal Locomotion. ACS APPLIED MATERIALS & INTERFACES 2022; 14:12936-12948. [PMID: 35244389 DOI: 10.1021/acsami.2c01838] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Soft-bodied aquatic invertebrates can overcome hydrodynamic resistance and display diverse locomotion modes in response to environmental cues. Exploring the dynamics of locomotion from bioinspired aquatic actuators will broaden the perspective of underwater manipulation of artificial systems in fluidic environments. Here, we report a multilayer soft actuator design based on a light-driven hydrogel and a laser-induced graphene (LIG) actuator, minimizing the effect of the time delay by a monolithic hydrogel-based system while maintaining shape-morphing functionality. Moreover, different time scales in the response of actuator materials enable a real-time desynchronization of energy inputs, holding great potential for applications requiring desynchronized stimulation. This hybrid design principle is ultimately demonstrated with a high-performance aquatic soft actuator possessing an underwater walking speed of 0.81 body length per minute at a relatively low power consumption of 3 W. When integrated with an optical sensor, the soft actuator can sense the variation in light intensity and achieve mediated reciprocal motion. Our proposed locomotion mechanism could inspire other multilayer soft actuators to achieve underwater functionalities at the same spatiotemporal scale. The underwater actuation platform could be used to study locomotion kinematics and control mechanisms that mimic the motion of soft-bodied aquatic organisms.
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Affiliation(s)
- Zhiqiang Yu
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems, Beijing Institute of Technology, Ministry of Education, Beijing 100081, China
| | - Junyi Shang
- School of Automation, Beijing Institute of Technology, Beijing 100081, China
| | - Qing Shi
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems, Beijing Institute of Technology, Ministry of Education, Beijing 100081, China
| | - Yuanqing Xia
- School of Automation, Beijing Institute of Technology, Beijing 100081, China
| | - Di-Hua Zhai
- School of Automation, Beijing Institute of Technology, Beijing 100081, China
| | - Huaping Wang
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems, Beijing Institute of Technology, Ministry of Education, Beijing 100081, China
| | - Qiang Huang
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems, Beijing Institute of Technology, Ministry of Education, Beijing 100081, China
| | - Toshio Fukuda
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems, Beijing Institute of Technology, Ministry of Education, Beijing 100081, China
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45
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Zhang J, Sun D, Zhang B, Sun Q, Zhang Y, Liu S, Wang Y, Liu C, Chen J, Chen J, Song Y, Liu X. Intrinsic carbon nanotube liquid crystalline elastomer photoactuators for high-definition biomechanics. MATERIALS HORIZONS 2022; 9:1045-1056. [PMID: 35040453 DOI: 10.1039/d1mh01810h] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Photoresponsive soft actuators with the unique merits of flexibility, contactless operation, and remote control have huge potential in technological applications of bionic robotics and biomedical devices. Herein, a facile strategy was proposed to prepare an intrinsically-photoresponsive elastomer by chemically grafting carbon nanotubes (CNTs) into a thermally-sensitive liquid-crystalline elastomer (LCE) network. Highly effective dispersion and nematic orientation of CNTs in the intrinsic LCE matrix were observed to yield anchoring energies ranging from 1.65 × 10-5 J m-2 to 5.49 × 10-7 J m-2, which significantly enhanced the mechanical and photothermal properties of the photoresponsive elastomer. When embedding an ultralow loading of CNTs (0.1 wt%), the tensile strength of the LCE increased by 420% to 13.89 MPa (||) and 530% to 3.94 MPa (⊥) and exhibited a stable response to repeated alternating cooling and heating cycles, as well as repeated UV and infrared irradiation. Furthermore, the shape transformation, locomotion, and photo-actuation capabilities allow the CNT/LCE actuator to be applied in high-definition biomechanical applications, such as phototactic flowers, serpentine robots and artificial muscles. This design strategy may provide a promising method to manufacture high-precision, remote-control smart devices.
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Affiliation(s)
- Juzhong Zhang
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Dandan Sun
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Bin Zhang
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Qingqing Sun
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Yang Zhang
- Center of Advanced Analysis & Gene Sequencing, Zhengzhou University, Zhengzhou, 450001, China
| | - Shuiren Liu
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Yaming Wang
- National Engineering Research Center for Advanced Polymer Processing Technology, Key Laboratory of Advanced Materials Processing & Mold, Ministry of Education, Zhengzhou University, Zhengzhou, 450001, China
| | - Chuntai Liu
- National Engineering Research Center for Advanced Polymer Processing Technology, Key Laboratory of Advanced Materials Processing & Mold, Ministry of Education, Zhengzhou University, Zhengzhou, 450001, China
| | - Jinzhou Chen
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Jingbo Chen
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
| | - Yanlin Song
- Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing, 100190, China
| | - Xuying Liu
- School of Materials Science and Engineering, Henan Key Laboratory of Advanced Nylon Materials and Application, Henan Innovation Center for Functional Polymer Membrane Materials, Zhengzhou University, Zhengzhou, 450001, China.
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46
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Zhao N, Wang X, Yao L, Yan H, Qin B, Li C, Zhang J. Actuation performance of a liquid crystalline elastomer composite reinforced by eiderdown fibers. SOFT MATTER 2022; 18:1264-1274. [PMID: 35044410 DOI: 10.1039/d1sm01356d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Liquid crystalline elastomer (LCE) materials have been developed and investigated for several decades. One important obstacle, which impedes the practical industrial application of LCE materials, is their modest robustness as actuator materials. In this work, we developed a LCE composite which was fabricated by incorporating eiderdown fibers into a polysiloxane-based main-chain LCE matrix. The eiderdown fibers were used as the flexible reinforcement phase suitable for the shape-morphing performance of LCE materials upon being stimulated. Due to the long fiber property, specific structure and surface characteristics of the eiderdown fibers, they constructed a reinforcement network in the LCE matrix and formed tight interfacial adhesion with the matrix. The LCE composite demonstrated enhanced actuation mechanical properties and robust actuation performance. Its actuation blocking stress and modulus were increased due to the reinforcement effect of the eiderdown fibers. The tensile strength and the performance of anti-fatigue failure under repeated actuation cycles and high loadings were greatly improved due to the crack-resisting effect and bridging effect of the eiderdown fibers. While other properties, such as the liquid crystalline phase structure, the stimulus deformation ratio, phase transition temperature of the LCE matrix, etc., did not deteriorate or change due to the high flexibility, thermal stability and chemical stability of the eiderdown fibers.
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Affiliation(s)
- Nan Zhao
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Xiuxiu Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Liru Yao
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Huixuan Yan
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Ban Qin
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Chensha Li
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China.
| | - Jianqi Zhang
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
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47
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Lin X, Zou W, Terentjev EM. Double Networks of Liquid-Crystalline Elastomers with Enhanced Mechanical Strength. Macromolecules 2022; 55:810-820. [PMID: 35572091 PMCID: PMC9097525 DOI: 10.1021/acs.macromol.1c02065] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 01/06/2022] [Indexed: 11/28/2022]
Abstract
![]()
Liquid-crystalline elastomers (LCEs)
are frequently used in soft
actuator development. However, applications are limited because LCEs
are prone to mechanical failure when subjected to heavy loads and
high temperatures during the working cycle. A mechanically tough LCE
system offers larger work capacity and lower failure rate for the
actuators. Herein, we adopt the double-network strategy, starting
with a siloxane-based exchangeable LCE and developing a series of
double-network liquid-crystalline elastomers (DN-LCEs) that are mechanically
tougher than the initial elastomer. We incorporate diacrylate reacting
monomers to fabricate DN-LCEs, some of which have the breaking stress
of 40 MPa. We incorporate thermoplastic polyurethane to fabricate
a DN-LCE, achieving an enormous ductility of 90 MJ/m3.
We have also attempted to utilize the aza-Michael chemistry to make
a DN-LCE that retains high plasticity because of several bond-exchange
mechanisms; however, it failed to produce a stable reprocessable LCE
system using conventional ester-based reactive mesogens. Each of these
DN-LCEs exhibits unique features and characteristics, which are compared
and discussed.
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Affiliation(s)
- Xueyan Lin
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Weike Zou
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
- State Key Laboratory of Chemical Engineering, Zhejiang University, Hangzhou 310027, P.R. China
| | - Eugene M. Terentjev
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
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48
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Ohzono T, Koyama E. Effects of photo-isomerizable side groups on the phase and mechanical properties of main-chain nematic elastomers. Polym Chem 2022. [DOI: 10.1039/d2py00256f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of main-chain nematic liquid crystal elastomers containing various photo-isomerizable side groups branching from the main chain were synthesized. The effects of the side groups on the thermal phase and mechanical properties were explored.
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Affiliation(s)
- Takuya Ohzono
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan
| | - Emiko Koyama
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan
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49
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Cheng M, Zeng H, Li Y, Liu J, Luo D, Priimagi A, Liu YJ. Light-Fueled Polymer Film Capable of Directional Crawling, Friction-Controlled Climbing, and Self-Sustained Motion on a Human Hair. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103090. [PMID: 34713627 PMCID: PMC8728837 DOI: 10.1002/advs.202103090] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/11/2021] [Indexed: 05/21/2023]
Abstract
Recent efforts in stimuli-responsive soft materials have enabled wirelessly controlled actuation with increasing degrees of freedom, yielding miniature robots capable of various locomotion in open environments such as on a plane or inside fluids. However, grand challenges remain in harnessing photomechanical deformation to induce locomotion and control of friction during the movement, especially for robotic actuations within constrained spaces. Here, the authors report a centimeter-long polymer strip made of a liquid crystal network that is capable of versatile light-fueled motions along a human hair. The soft polymer robot can translocate directionally upon temporally modulated excitation and climb vertically through friction control with light. A self-oscillating strip is demonstrated to continuously translocate along the hair upon a constant light stimulus, and its gaiting is associated to the smoothness of the hair surface. The results offer new insights to small-scale photo-actuator, mechanical control, and automation in soft micro robotics.
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Affiliation(s)
- Ming Cheng
- Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen518055China
| | - Hao Zeng
- Smart Photonic MaterialsFaculty of Engineering and Natural SciencesTampere UniversityP.O. Box 541TampereFI‐33101Finland
| | - Yifei Li
- Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen518055China
| | - Jianxun Liu
- Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen518055China
| | - Dan Luo
- Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen518055China
| | - Arri Priimagi
- Smart Photonic MaterialsFaculty of Engineering and Natural SciencesTampere UniversityP.O. Box 541TampereFI‐33101Finland
| | - Yan Jun Liu
- Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen518055China
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50
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Abstract
In contrast to conventional hard actuators, soft actuators offer many vivid advantages, such as improved flexibility, adaptability, and reconfigurability, which are intrinsic to living systems. These properties make them particularly promising for different applications, including soft electronics, surgery, drug delivery, artificial organs, or prosthesis. The additional degree of freedom for soft actuatoric devices can be provided through the use of intelligent materials, which are able to change their structure, macroscopic properties, and shape under the influence of external signals. The use of such intelligent materials allows a substantial reduction of a device's size, which enables a number of applications that cannot be realized by externally powered systems. This review aims to provide an overview of the properties of intelligent synthetic and living/natural materials used for the fabrication of soft robotic devices. We discuss basic physical/chemical properties of the main kinds of materials (elastomers, gels, shape memory polymers and gels, liquid crystalline elastomers, semicrystalline ferroelectric polymers, gels and hydrogels, other swelling polymers, materials with volume change during melting/crystallization, materials with tunable mechanical properties, and living and naturally derived materials), how they are related to actuation and soft robotic application, and effects of micro/macro structures on shape transformation, fabrication methods, and we highlight selected applications.
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Affiliation(s)
- Indra Apsite
- Faculty of Engineering Science, Department of Biofabrication, University of Bayreuth, Ludwig Thoma Str. 36A, 95447 Bayreuth, Germany
| | - Sahar Salehi
- Department of Biomaterials, Center of Energy Technology und Materials Science, University of Bayreuth, Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Leonid Ionov
- Faculty of Engineering Science, Department of Biofabrication, University of Bayreuth, Ludwig Thoma Str. 36A, 95447 Bayreuth, Germany.,Bavarian Polymer Institute, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
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