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Chen W, Tong D, Meng L, Tan B, Lan R, Zhang Q, Yang H, Wang C, Liu K. Knotted Artificial Muscles for Bio-Mimetic Actuation under Deepwater. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2400763. [PMID: 38641927 DOI: 10.1002/adma.202400763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/07/2024] [Indexed: 04/21/2024]
Abstract
Muscles featuring high frequency and high stroke linear actuation are essential for animals to achieve superior maneuverability, agility, and environmental adaptability. Artificial muscles are yet to match their biological counterparts, due to inferior actuation speed, magnitude, mode, or adaptability. Inspired by the hierarchical structure of natural muscles, artificial muscles are created that are powerful, responsive, robust, and adaptable. The artificial muscles consist of knots braided from 3D printed liquid crystal elastomer fibers and thin heating threads. The unique hierarchical, braided knot structure offers amplified linear stroke, force rate, and damage-tolerance, as verified by both numerical simulations and experiments. In particular, the square knotted artificial muscle shows reliable cycles of actuation at 1Hz in 3000m depth underwater. Potential application is demonstrated by propelling a model boat. Looking ahead, the knotted artificial muscles can empower novel biomedical devices and soft robots to explore various environments, from inside human body to the mysterious deep sea.
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Affiliation(s)
- Wenhui Chen
- Department of Advanced Manufacturing and Robotics, Peking University, No. 5 Yiheyuan Rd., Beijing, 100871, China
| | - Dezhong Tong
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, California, 90095, USA
| | - Linghan Meng
- Shenyang Institute of Automation, Chinese Academy of Sciences, No. 135 Chuangxin Rd., Shenyang, 110169, China
| | - Bowen Tan
- Department of Advanced Manufacturing and Robotics, Peking University, No. 5 Yiheyuan Rd., Beijing, 100871, China
| | - Ruochen Lan
- School of Materials Science and Engineering, Peking University, No. 5 Yiheyuan Rd., Beijing, 100871, China
| | - Qifeng Zhang
- Shenyang Institute of Automation, Chinese Academy of Sciences, No. 135 Chuangxin Rd., Shenyang, 110169, China
| | - Huai Yang
- School of Materials Science and Engineering, Peking University, No. 5 Yiheyuan Rd., Beijing, 100871, China
| | - Cong Wang
- Shenyang Institute of Automation, Chinese Academy of Sciences, No. 135 Chuangxin Rd., Shenyang, 110169, China
| | - Ke Liu
- Department of Advanced Manufacturing and Robotics, Peking University, No. 5 Yiheyuan Rd., Beijing, 100871, China
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2
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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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3
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Kotikian A, Watkins AA, Bordiga G, Spielberg A, Davidson ZS, Bertoldi K, Lewis JA. Liquid Crystal Elastomer Lattices with Thermally Programmable Deformation via Multi-Material 3D Printing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2310743. [PMID: 38189562 DOI: 10.1002/adma.202310743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/09/2023] [Indexed: 01/09/2024]
Abstract
An integrated design, modeling, and multi-material 3D printing platform for fabricating liquid crystal elastomer (LCE) lattices in both homogeneous and heterogeneous layouts with spatially programmable nematic director order and local composition is reported. Depending on their compositional topology, these lattices exhibit different reversible shape-morphing transformations upon cycling above and below their respective nematic-to-isotropic transition temperatures. Further, it is shown that there is good agreement between their experimentally observed deformation response and model predictions for all LCE lattice designs evaluated. Lastly, an inverse design model is established and the ability to print LCE lattices with the predicted deformation behavior is demonstrated. This work opens new avenues for creating architected LCE lattices that may find potential application in energy-dissipating structures, microfluidic pumping, mechanical logic, and soft robotics.
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Affiliation(s)
- Arda Kotikian
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - Audrey A Watkins
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Giovanni Bordiga
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Andrew Spielberg
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - Zoey S Davidson
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - Katia Bertoldi
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Jennifer A Lewis
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
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Li S, Aizenberg M, Lerch MM, Aizenberg J. Programming Deformations of 3D Microstructures: Opportunities Enabled by Magnetic Alignment of Liquid Crystalline Elastomers. ACCOUNTS OF MATERIALS RESEARCH 2023; 4:1008-1019. [PMID: 38148997 PMCID: PMC10749463 DOI: 10.1021/accountsmr.3c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 09/10/2023] [Indexed: 12/28/2023]
Abstract
Synthetic structures that undergo controlled movement are crucial building blocks for developing new technologies applicable to robotics, healthcare, and sustainable self-regulated materials. Yet, programming motion is nontrivial, and particularly at the microscale it remains a fundamental challenge. At the macroscale, movement can be controlled by conventional electric, pneumatic, or combustion-based machinery. At the nanoscale, chemistry has taken strides in enabling molecularly fueled movement. Yet in between, at the microscale, top-down fabrication becomes cumbersome and expensive, while bottom-up chemical self-assembly and amplified molecular motion does not reach the necessary sophistication. Hence, new approaches that converge top-down and bottom-up methods and enable motional complexity at the microscale are urgently needed. Synthetic anisotropic materials (e.g., liquid crystalline elastomers, LCEs) with encoded molecular anisotropy that are shaped into arbitrary geometries by top-down fabrication promise new opportunities to implement controlled actuation at the microscale. In such materials, motional complexity is directly linked to the built-in molecular anisotropy that can be "activated" by external stimuli. So far, encoding the desired patterns of molecular directionality has relied mostly on either mechanical or surface alignment techniques, which do not allow the decoupling of molecular and geometric features, severely restricting achievable material shapes and thus limiting attainable actuation patterns, unless complex multimaterial constructs are fabricated. Electromagnetic fields have recently emerged as possible alternatives to provide 3D control over local anisotropy, independent of the geometry of a given 3D object. The combination of magnetic alignment and soft lithography, in particular, provides a powerful platform for the rapid, practical, and facile production of microscale soft actuators with field-defined local anisotropy. Recent work has established the feasibility of this approach with low magnetic field strengths (in the lower mT range) and comparably simple setups used for the fabrication of the microactuators, in which magnetic fields can be engineered through arrangement of permanent magnets. This workflow gives access to microstructures with unusual spatial patterning of molecular alignment and has enabled a multitude of nontrivial deformation types that would not be possible to program by any other means at the micron scale. A range of "activating" stimuli can be used to put these structures in motion, and the type of the trigger plays a key role too: directional and dynamic stimuli (such as light) make it possible to activate the patterned anisotropic material locally and transiently, which enables one to achieve and further program motional complexity and communication in microactuators. In this Account, we will discuss recent advances in magnetic alignment of molecular anisotropy and its use in soft lithography and related fabrication approaches to create LCE microactuators. We will examine how design choices-from the molecular to the fabrication and the operational levels-control and define the achievable LCE deformations. We then address the role of stimuli in realizing the motional complexity and how one can engineer feedback within and communication between microactuator arrays fabricated by soft lithography. Overall, we outline emerging strategies that make possible a completely new approach to designing for desired sets of motions of active, microscale objects.
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Affiliation(s)
- Shucong Li
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
- Department
of Mechanical Engineering, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael Aizenberg
- John
A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Michael M. Lerch
- John
A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Stratingh
Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Joanna Aizenberg
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
- John
A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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Hu Z, Zhang Y, Jiang H, Lv JA. Bioinspired helical-artificial fibrous muscle structured tubular soft actuators. SCIENCE ADVANCES 2023; 9:eadh3350. [PMID: 37352358 PMCID: PMC10289666 DOI: 10.1126/sciadv.adh3350] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/19/2023] [Indexed: 06/25/2023]
Abstract
Biological tubular actuators show diverse deformations, which allow for sophisticated deformations with well-defined degrees of freedom (DOF). Nonetheless, synthetic active tubular soft actuators largely only exhibit few simple deformations with limited and undesignable DOF. Inspired by 3D fibrous architectures of tubular muscular hydrostats, we devised conceptually new helical-artificial fibrous muscle structured tubular soft actuators (HAFMS-TSAs) with locally tunable molecular orientations, materials, mechanics, and actuation via a modular fabrication platform using a programmable filament winding technique. Unprecedentedly, HAFMS-TSAs can be endowed with 11 different morphing modes through programmable regulation of their 3D helical fibrous architectures. We demonstrate a single "living" artificial plant rationally structured by HAFMS-TSAs exhibiting diverse photoresponsive behaviors that enable adaptive omnidirectional reorientation of its hierarchical 3D structures in the response to environmental irradiation, resembling morphing intelligence of living plants in reacting to changing environments. Our methodology would be significantly beneficial for developing sophisticated soft actuators with designable and tunable DOF.
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Affiliation(s)
- Zhiming Hu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, Zhejiang, China
- School of Engineering, Westlake University, Hangzhou 310030, Zhejiang, China
- Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Yanlin Zhang
- School of Engineering, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Hanqing Jiang
- School of Engineering, Westlake University, Hangzhou 310030, Zhejiang, China
- Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China
| | - Jiu-an Lv
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, Zhejiang, China
- School of Engineering, Westlake University, Hangzhou 310030, Zhejiang, China
- Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
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6
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Liu M, Jin L, Yang S, Wang Y, Murray CB, Yang S. Shape Morphing Directed by Spatially Encoded, Dually Responsive Liquid Crystalline Elastomer Micro-Actuators. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208613. [PMID: 36341507 DOI: 10.1002/adma.202208613] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Liquid crystalline elastomers (LCEs) with intrinsic molecular anisotropy can be programmed to morph shapes under external stimuli. However, it is difficult to program the position and orientation of individual mesogenic units separately and locally, whether in-plane or out-of-plane, since each mesogen is linked to adjacent ones through the covalently bonded polymer chains. Here, dually responsive, spindle-shaped micro-actuators are synthesized from LCE composites, which can reorient under a magnetic field and change the shape upon heating. When the discrete micro-actuators are embedded in a conventional and nonresponsive elastomer with programmed height distribution and in-plane orientation in local regions, robust and complex shape morphing induced by the cooperative actuations of the locally distributed micro-actuators, which corroborates with finite element analysis, are shown. The spatial encoding of discrete micro-actuators in a nonresponsive matrix allows to decouple the actuators and the matrix, broadening the material palette to program local and global responses to stimuli for applications including soft robotics, smart wearables, and sensors.
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Affiliation(s)
- Mingzhu Liu
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lishuai Jin
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shengsong Yang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yuchen Wang
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Christopher B Murray
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shu Yang
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
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7
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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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8
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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: 5] [Impact Index Per Article: 2.5] [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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