151
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Kuang X, Roach DJ, Hamel CM, Yu K, Qi HJ. Materials, design, and fabrication of shape programmable polymers. ACTA ACUST UNITED AC 2020. [DOI: 10.1088/2399-7532/aba1d9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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152
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Dai H, Dong Z, Jiang L. Directional liquid dynamics of interfaces with superwettability. SCIENCE ADVANCES 2020; 6:eabb5528. [PMID: 32917681 PMCID: PMC11206479 DOI: 10.1126/sciadv.abb5528] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Natural creatures use their surface structures to control directional liquid dynamics for survival. Learning from nature, artificial superwetting materials have triggered technological revolutions in many disciplines. To improve controllability, researchers have attempted to use external fields, such as thermal, light, magnetic, and electric fields, to assist or achieve controllable liquid dynamics. Emerging directional liquid transport applications have prosperously advanced in recent years but still present some challenges. This review discusses and summarizes the field of directional liquid dynamics on natural creatures and artificial surfaces with superwettabilities and ventures to propose several potential strategies to construct directional liquid transport systems for fog collection, 3D printing, energy devices, separation, soft machine, and sensor devices, which are useful for driving liquid transport or motility.
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Affiliation(s)
- Haoyu Dai
- CAS Key Laboratory of Bio-inspired Materials and Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 101407, China
| | - Zhichao Dong
- CAS Key Laboratory of Bio-inspired Materials and Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 101407, China
| | - Lei Jiang
- CAS Key Laboratory of Bio-inspired Materials and Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 101407, China
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Chemistry, Beihang University, Beijing 100191, China
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153
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Wang Z, Wang Z, Zheng Y, He Q, Wang Y, Cai S. Three-dimensional printing of functionally graded liquid crystal elastomer. SCIENCE ADVANCES 2020; 6:eabc0034. [PMID: 32978149 PMCID: PMC7518867 DOI: 10.1126/sciadv.abc0034] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/06/2020] [Indexed: 05/04/2023]
Abstract
As a promising actuating material, liquid crystal elastomer (LCE) has been intensively explored in building diverse active structures and devices. Recently, direct ink writing technique has been developed to print LCE structures with various geometries and actuation behaviors. Despite the advancement in printing LCE, it remains challenging to print three-dimensional (3D) LCE structures with graded properties. Here, we report a facile method to tailor both the actuation behavior and mechanical properties of printed LCE filaments by varying printing parameters. On the basis of the comprehensive processing-structure-property relationship, we propose a simple strategy to print functionally graded LCEs, which greatly increases the design space for creating active morphing structures. We further demonstrate mitigation of stress concentration near the interface between an actuatable LCE tube and a rigid glass plate through gradient printing. The strategy developed here will facilitate potential applications of LCEs in different fields.
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Affiliation(s)
- Zijun Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zhijian Wang
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Yue Zheng
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qiguang He
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yang Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shengqiang Cai
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA.
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
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154
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Wang S, Gao Y, Wei A, Xiao P, Liang Y, Lu W, Chen C, Zhang C, Yang G, Yao H, Chen T. Asymmetric elastoplasticity of stacked graphene assembly actualizes programmable untethered soft robotics. Nat Commun 2020; 11:4359. [PMID: 32868779 PMCID: PMC7459344 DOI: 10.1038/s41467-020-18214-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022] Open
Abstract
There is ever-increasing interest yet grand challenge in developing programmable untethered soft robotics. Here we address this challenge by applying the asymmetric elastoplasticity of stacked graphene assembly (SGA) under tension and compression. We transfer the SGA onto a polyethylene (PE) film, the resulting SGA/PE bilayer exhibits swift morphing behavior in response to the variation of the surrounding temperature. With the applications of patterned SGA and/or localized tempering pretreatment, the initial configurations of such thermal-induced morphing systems can also be programmed as needed, resulting in diverse actuation systems with sophisticated three-dimensional structures. More importantly, unlike the normal bilayer actuators, our SGA/PE bilayer, after a constrained tempering process, will spontaneously curl into a roll, which can achieve rolling locomotion under infrared lighting, yielding an untethered light-driven motor. The asymmetric elastoplasticity of SGA endows the SGA-based bi-materials with great application promise in developing untethered soft robotics with high configurational programmability.
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Affiliation(s)
- Shuai Wang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
- School of Chemical Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, People's Republic of China
| | - Yang Gao
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
- The Hong Kong Polytechnic University Shenzhen Research Institute, 518057, Shenzhen, People's Republic of China
| | - Anran Wei
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
| | - Peng Xiao
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China.
- School of Chemical Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, People's Republic of China.
| | - Yun Liang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
- School of Chemical Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, People's Republic of China
| | - Wei Lu
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
- School of Chemical Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, People's Republic of China
| | - Chinyin Chen
- Zhejiang Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
| | - Chi Zhang
- Zhejiang Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
| | - Guilin Yang
- Zhejiang Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China
| | - Haimin Yao
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China.
- The Hong Kong Polytechnic University Shenzhen Research Institute, 518057, Shenzhen, People's Republic of China.
| | - Tao Chen
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 315201, Ningbo, People's Republic of China.
- School of Chemical Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, People's Republic of China.
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155
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Liu M, Domino L, Vella D. Tapered elasticæ as a route for axisymmetric morphing structures. SOFT MATTER 2020; 16:7739-7750. [PMID: 32743628 DOI: 10.1039/d0sm00714e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transforming flat two-dimensional (2D) sheets into three-dimensional (3D) structures by combining carefully made cuts with applied edge-loads has emerged as an exciting manufacturing paradigm in a range of applications from mechanical metamaterials to flexible electronics. In Kirigami, patterns of cuts are introduced that allow solid faces to rotate about each other, deforming in three dimensions whilst remaining planar. In other scenarios, however, the solid elements bend in one direction. In this paper, we model such bending deformations using the formulation of an elastic strip whose thickness and width are tapered (the 'tapered elastica'). We show how this framework can be exploited to design the tapering patterns required to create planar sheets that morph into desired axisymmetric 3D shapes under a combination of horizontal and vertical edge-loads. We exhibit this technique by recreating miniature structures with positive, negative, and variable apparent Gaussian curvatures. With sheets of constant thickness, the resulting morphed shapes may leave gaps between the deformed elements. However, by tapering the thickness of the sheet too, these gaps can be closed, creating tessellated three-dimensional structures. Our theoretical approaches are verified by both numerical simulations and physical experiments.
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Affiliation(s)
- Mingchao Liu
- Mathematical Institute, University of Oxford, Oxford, OX2 6GG, UK.
| | - Lucie Domino
- Mathematical Institute, University of Oxford, Oxford, OX2 6GG, UK.
| | - Dominic Vella
- Mathematical Institute, University of Oxford, Oxford, OX2 6GG, UK.
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156
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Zhao T, Dou W, Hu Z, Hou W, Sun Y, Lv JA. Reconfigurable Soft Actuators with Multiple-Stimuli Responses. Macromol Rapid Commun 2020; 41:e2000313. [PMID: 32767476 DOI: 10.1002/marc.202000313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/20/2020] [Indexed: 12/26/2022]
Abstract
Multiple-stimuli responsive soft actuators with tunable initial shapes would have substantial potential in broad technological applications, ranging from advanced sensors, smart robots to biomedical devices. However, existing soft actuators are often limited to single initial shape and are unable to reversibly reconfigure into desirable shapes, which severely restricts the multifunctions that can be integrated into one actuator. Here, a novel reconfigurable supramolecular polymer/polyethylene terephthalate (PET) bilayer actuator exhibiting multiple-stimuli responses is presented. In this bilayer actuator, the supramolecular polymer layer constructed of poly(5-Norbornene-2-carboxylic acid-1,3-cyclooctadiene) (PNCCO) and azopyridine derivative (PyAzoPy) via H-bonds provides multiple-stimuli responses: PyAzoPy offers light response and carboxylic groups in PNCCO endow the actuator with humidity response. Meanwhile thermoplastic PET layer enables the bilayer actuators to be reconfigured into various shapes by thermal stimuli. The rationally designed actuators exhibit versatile capabilities to reversibly reconfigure into a set of initial shapes and carry out multiple functions, such as photo-driven "foldback-clip" and Ω-shaped crawling robots. In addition, bio-inspired plants constructed by reconfiguration of such actuators demonstrate reversible multiple-stimuli responses. It is anticipated that these novel actuators with highly tunable geometries and actuation modes would be useful to develop multifunctional devices capable of performing diverse tasks.
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Affiliation(s)
- Tonghui Zhao
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.,Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Wenchao Dou
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Zhiming Hu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.,Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Wenhao Hou
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.,Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Yirui Sun
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Jiu-An Lv
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China.,Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
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157
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He Q, Wang Z, Wang Y, Song Z, Cai S. Recyclable and Self-Repairable Fluid-Driven Liquid Crystal Elastomer Actuator. ACS APPLIED MATERIALS & INTERFACES 2020; 12:35464-35474. [PMID: 32658448 DOI: 10.1021/acsami.0c10021] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Liquid crystal elastomer (LCE) is a newly emerging soft actuating material that has been extensively explored for building novel soft robots and diverse active devices, thanks to its large actuation stress and strain, high work density, and versatile actuation modes. However, there have also been several widely recognized limitations of LCE-based actuators for practical applications, including slow response and narrow range of operation temperature. Herein, we develop fluid-driven disulfide LCE actuators through facile laminate manufacturing enabled by a dynamic bond exchange reaction. Because of the merits of the active heating/cooling mechanism of the fluidic structure, this newly developed disulfide LCE actuator can generate large cyclic actuation at a frequency around 1 Hz and can operate in a wide range of temperatures. The unique combination of the fluidic structure design and the dynamic covalent bonds in the elastomer has also enabled the full recyclability and self-repairability of the actuator. Using the newly developed actuator as building block, we further constructed soft robotic systems that can realize manipulating and programmable movement. The design principle demonstrated in the current work opens a promising avenue for exploring more novel applications of LCE-based soft actuators.
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Affiliation(s)
- Qiguang He
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Zhijian Wang
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Yang Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, United States
| | - Zhaoqiang Song
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, United States
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158
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Wan X, Luo L, Liu Y, Leng J. Direct Ink Writing Based 4D Printing of Materials and Their Applications. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001000. [PMID: 32832355 PMCID: PMC7435246 DOI: 10.1002/advs.202001000] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/30/2020] [Indexed: 05/19/2023]
Abstract
4D printing has attracted academic interest in the recent years because it endows static printed structures with dynamic properties with the change of time. The shapes, functionalities, or properties of the 4D printed objects could alter under various stimuli such as heat, light, electric, and magnetic field. Briefly, 4D printing is the development of 3D printing with the fourth dimension of time. Among the fabrication techniques that have been employed for 4D printing, the direct ink writing technique shows superiority due to its open source for various types of materials. Herein, the state-of-the-art achievements about the topic of 4D printing through direct ink writing are summarized. The types of materials, printing strategies, actuated methods, and their potential applications are discussed in detail. To date, most efforts have been devoted to shape-shifting materials, including shape memory polymers, hydrogels, and liquid crystal elastomers, showing great prospects in areas ranging from the biomedical field to robotics. Finally, the current challenges and outlook toward 4D printing based on direct ink writing are also pointed out to leave open a significant space for future innovation.
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Affiliation(s)
- Xue Wan
- Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin150080P. R. China
| | - Lan Luo
- Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin150080P. R. China
| | - Yanju Liu
- Department of Astronautical Science and MechanicsHarbin Institute of TechnologyHarbin150001P. R. China
| | - Jinsong Leng
- Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin150080P. R. China
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159
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Ohzono T, Norikane Y, Saed MO, Terentjev EM. Light-Driven Dynamic Adhesion on Photosensitized Nematic Liquid Crystalline Elastomers. ACS APPLIED MATERIALS & INTERFACES 2020; 12:31992-31997. [PMID: 32609481 DOI: 10.1021/acsami.0c08289] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In liquid crystal elastomers (LCEs), the internal mechanical loss increases around the nematic-isotropic phase transition and remains high all through the nematic phase, originating from the internal orientational relaxation related to the so-called "soft elasticity". Because the viscoelastic dissipation of the materials affects their adhesion properties, the nematic-isotropic phase transition can cause dramatic changes in the adhesion strength. Although the phase transitions can generally be induced by heat, here, we demonstrate the light-driven transition in dynamic adhesion in dye-doped nematic LCE. The special dye is chosen to efficiently generate local heat on light absorption. The adhesion strength is lowered with fine tunability depending on the light power, which governs the effective local temperature and through that the viscoelastic damping of the system. We demonstrate the light-assisted dynamic control of adhesion in a 90°-peel test and in pick-and-release of objects, which may lead to the development of stimuli-responsive adhesive systems with fine spatio-temporal controls.
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Affiliation(s)
- Takuya Ohzono
- Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan
| | - Yasuo Norikane
- Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan
| | - Mohand O Saed
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
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160
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Ford MJ, Palaniswamy M, Ambulo CP, Ware TH, Majidi C. Size of liquid metal particles influences actuation properties of a liquid crystal elastomer composite. SOFT MATTER 2020; 16:5878-5885. [PMID: 32412038 DOI: 10.1039/d0sm00278j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Composites of liquid crystal elastomer (LCE) that are electrically conductive have the potential to function as soft "artificial muscle" actuators that can be reversibly stimulated with electrical Joule-heating. Conductivity can be achieved by embedding the LCE with droplets of an alloy of gallium and indium that is liquid at room temperature. These soft artificial muscles are capable of >50% reversible actuation with an applied load. The key to actuation at high loadings of liquid metal (LM) is that the droplets deform with the surrounding matrix. By controlling the size of LM droplets through simple processing techniques, we show that the actuator properties of the LM-LCE muscle can be tuned. For example, composites with smaller liquid metal particles (ca. 10 μm or less) are stiffer than those with larger liquid metal particles (ca. >100 μm) and are capable of greater force output. However, smaller particles reduce actuation strain and composites with large particles exhibit significantly greater stroke length. Such tunability in actuation properties permits the fabrication of specialized soft artificial muscles, where processing of the composite controls actuation strain and actuation force.
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Affiliation(s)
- Michael J Ford
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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161
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Bai K, Cheng X, Xue Z, Song H, Sang L, Zhang F, Liu F, Luo X, Huang W, Huang Y, Zhang Y. Geometrically reconfigurable 3D mesostructures and electromagnetic devices through a rational bottom-up design strategy. SCIENCE ADVANCES 2020; 6:eabb7417. [PMID: 32832676 PMCID: PMC7439572 DOI: 10.1126/sciadv.abb7417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/05/2020] [Indexed: 05/07/2023]
Abstract
Microelectronic devices with reconfigurable three-dimensional (3D) microarchitecture that can be repetitively switched among different geometrical and/or working states have promising applications in widespread areas. Traditional approaches usually rely on stimulated deformations of active materials under external electric/magnetic fields, which could potentially introduce parasitic side effects and lower device performances. Development of a rational strategy that allows access to high-performance 3D microdevices with multiple stable geometric configurations remains challenging. We introduce a mechanically guided scheme to build geometrically reconfigurable 3D mesostructures through a bottom-up design strategy based on a class of elementary reconfigurable structures with the simplest ribbon geometries. Quantitative mechanics modeling of the structural reconfigurability allows for the development of phase diagrams and design maps. Demonstrations of ~30 reconfigurable mesostructures with diverse geometric topologies and characteristic dimensions illustrate the versatile applicability. The multimode nature enables customized distinct beamforming and discrete beam scanning using a single antenna capable of on-demand reconfiguration.
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Affiliation(s)
- Ke Bai
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Xu Cheng
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Zhaoguo Xue
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Honglie Song
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Lei Sang
- School of Microelectronics, Hefei University of Technology, Anhui 230009, P.R. China
| | - Fan Zhang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Fei Liu
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Xiang Luo
- School of Microelectronics, Hefei University of Technology, Anhui 230009, P.R. China
| | - Wen Huang
- School of Microelectronics, Hefei University of Technology, Anhui 230009, P.R. China
| | - Yonggang Huang
- Departments of Civil and Environmental Engineering, Mechanical Engineering, and Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yihui Zhang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
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162
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Traugutt NA, Mistry D, Luo C, Yu K, Ge Q, Yakacki CM. Liquid-Crystal-Elastomer-Based Dissipative Structures by Digital Light Processing 3D Printing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000797. [PMID: 32508011 DOI: 10.1002/adma.202000797] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/20/2020] [Indexed: 05/24/2023]
Abstract
Digital Light Processing (DLP) 3D printing enables the creation of hierarchical complex structures with specific micro- and macroscopic architectures that are impossible to achieve through traditional manufacturing methods. Here, this hierarchy is extended to the mesoscopic length scale for optimized devices that dissipate mechanical energy. A photocurable, thus DLP-printable main-chain liquid crystal elastomer (LCE) resin is reported and used to print a variety of complex, high-resolution energy-dissipative devices. Using compressive mechanical testing, the stress-strain responses of 3D-printed LCE lattice structures are shown to have 12 times greater rate-dependence and up to 27 times greater strain-energy dissipation compared to those printed from a commercially available photocurable elastomer resin. The reported behaviors of these structures provide further insight into the much-overlooked energy-dissipation properties of LCEs and can inspire the development of high-energy-absorbing device applications.
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Affiliation(s)
- Nicholas A Traugutt
- University of Colorado Denver, 1200 Larimer Street, Campus Box 112, Denver, CO, 80217, USA
| | - Devesh Mistry
- University of Colorado Denver, 1200 Larimer Street, Campus Box 112, Denver, CO, 80217, USA
| | - Chaoqian Luo
- University of Colorado Denver, 1200 Larimer Street, Campus Box 112, Denver, CO, 80217, USA
| | - Kai Yu
- University of Colorado Denver, 1200 Larimer Street, Campus Box 112, Denver, CO, 80217, USA
| | - Qi Ge
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen, 518055, P. R. China
| | - Christopher M Yakacki
- University of Colorado Denver, 1200 Larimer Street, Campus Box 112, Denver, CO, 80217, USA
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163
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Saed MO, Terentjev EM. Catalytic Control of Plastic Flow in Siloxane-Based Liquid Crystalline Elastomer Networks. ACS Macro Lett 2020; 9:749-755. [PMID: 35648563 DOI: 10.1021/acsmacrolett.0c00265] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Liquid crystalline elastomer networks cross-linked by dynamic covalent bonds (xLCE) have the ability to be (re)processed during the plastic flow. However, the current bond-exchange strategies that are used to induce plastic flow in xLCE lack the efficient method to control the elastic-plastic transition. Here we describe a straightforward method to manipulate the transition to plastic flow via the choice of catalyst in xLCE cross-linked by siloxane. The nature and the amount of catalyst have a profound effect on the elastic-plastic transition temperature, and the stress relaxation behavior of the network. The temperature of fast plastic flow and the associated bond-exchange activation energy varied from 120 °C and 83 kJ/mol in the "fastest" exchange promoted by triazobicyclodecene (TBD) to 240 °C and 164 kJ/mol in the "slowest" exchange with triphenylphosphine (PPH), with a range of catalysts in between. We have identified the optimum conditions for programming an aligned monodomain xLCE, high programming temperature (230 °C) and low nematic to isotropic transition (60 °C), to achieve thermally and mechanically stable actuators.
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Affiliation(s)
- Mohand O. Saed
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Eugene M. Terentjev
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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164
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Herbert KM, Getty PT, Dolinski ND, Hertzog JE, de Jong D, Lettow JH, Romulus J, Onorato JW, Foster EM, Rowan SJ. Dynamic reaction-induced phase separation in tunable, adaptive covalent networks. Chem Sci 2020; 11:5028-5036. [PMID: 34122959 PMCID: PMC8159224 DOI: 10.1039/d0sc00605j] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/25/2020] [Indexed: 01/17/2023] Open
Abstract
A series of catalyst-free, room temperature dynamic bonds derived from a reversible thia-Michael reaction are utilized to access mechanically robust dynamic covalent network films. The equilibrium of the thiol addition to benzalcyanoacetate-based Michael-acceptors can be directly tuned by controlling the electron-donating/withdrawing nature of the Michael-acceptor. By modulating the composition of different Michael-acceptors in a dynamic covalent network, a wide range of mechanical properties and thermal responses can be realized. Additionally, the reported systems phase-separate in a process, coined dynamic reaction-induced phase separation (DRIPS), that yields reconfigurable phase morphologies and reprogrammable shape-memory behaviour as highlighted by the heat-induced folding of a predetermined structure.
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Affiliation(s)
- Katie M Herbert
- Pritzker School of Molecular Engineering, University of Chicago Chicago IL 60637 USA
| | - Patrick T Getty
- Pritzker School of Molecular Engineering, University of Chicago Chicago IL 60637 USA
| | - Neil D Dolinski
- Pritzker School of Molecular Engineering, University of Chicago Chicago IL 60637 USA
| | - Jerald E Hertzog
- Department of Chemistry, University of Chicago Chicago IL 60637 USA
| | - Derek de Jong
- The University of Chicago Laboratory Schools 1362 E. 59th St. Chicago IL 60637 USA
| | - James H Lettow
- Pritzker School of Molecular Engineering, University of Chicago Chicago IL 60637 USA
| | - Joy Romulus
- Department of Macromolecular Science and Engineering, Case Western Reserve University 2100 Adelbert Road Cleveland OH 44106 USA
| | - Jonathan W Onorato
- Department of Macromolecular Science and Engineering, Case Western Reserve University 2100 Adelbert Road Cleveland OH 44106 USA
| | - Elizabeth M Foster
- Department of Macromolecular Science and Engineering, Case Western Reserve University 2100 Adelbert Road Cleveland OH 44106 USA
| | - Stuart J Rowan
- Pritzker School of Molecular Engineering, University of Chicago Chicago IL 60637 USA
- Department of Chemistry, University of Chicago Chicago IL 60637 USA
- Chemical Science and Engineering Division and Center for Molecular Engineering, Argonne National Laboratory 9700 S. Cass Ave., Lemont IL 60434 USA
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165
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Sitti M, Wiersma DS. Pros and Cons: Magnetic versus Optical Microrobots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906766. [PMID: 32053227 DOI: 10.1002/adma.201906766] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/21/2019] [Indexed: 05/21/2023]
Abstract
Mobile microrobotics has emerged as a new robotics field within the last decade to create untethered tiny robots that can access and operate in unprecedented, dangerous, or hard-to-reach small spaces noninvasively toward disruptive medical, biotechnology, desktop manufacturing, environmental remediation, and other potential applications. Magnetic and optical actuation methods are the most widely used actuation methods in mobile microrobotics currently, in addition to acoustic and biological (cell-driven) actuation approaches. The pros and cons of these actuation methods are reported here, depending on the given context. They can both enable long-range, fast, and precise actuation of single or a large number of microrobots in diverse environments. Magnetic actuation has unique potential for medical applications of microrobots inside nontransparent tissues at high penetration depths, while optical actuation is suitable for more biotechnology, lab-/organ-on-a-chip, and desktop manufacturing types of applications with much less surface penetration depth requirements or with transparent environments. Combining both methods in new robot designs can have a strong potential of combining the pros of both methods. There is still much progress needed in both actuation methods to realize the potential disruptive applications of mobile microrobots in real-world conditions.
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Affiliation(s)
- Metin Sitti
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - Diederik S Wiersma
- LENS, University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
- INRIM, Strada delle Cacce 91, 10135, Torino, Italy
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166
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Wang XQ, Chan KH, Cheng Y, Ding T, Li T, Achavananthadith S, Ahmet S, Ho JS, Ho GW. Somatosensory, Light-Driven, Thin-Film Robots Capable of Integrated Perception and Motility. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000351. [PMID: 32285545 DOI: 10.1002/adma.202000351] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 05/21/2023]
Abstract
Living organisms are capable of sensing and responding to their environment through reflex-driven pathways. The grand challenge for mimicking such natural intelligence in miniature robots lies in achieving highly integrated body functionality, actuation, and sensing mechanisms. Here, somatosensory light-driven robots (SLiRs) based on a smart thin-film composite tightly integrating actuation and multisensing are presented. The SLiR subsumes pyro/piezoelectric responses and piezoresistive strain sensation under a photoactuator transducer, enabling simultaneous yet non-interfering perception of its body temperature and actuation deformation states. The compact thin film, when combined with kirigami, facilitates rapid customization of low-profile structures for morphable, mobile, and multiple robotic functionality. For example, an SLiR walker can move forward on different surfaces, while providing feedback on its detailed locomotive gaits and subtle terrain textures, and an SLiR anthropomorphic hand shows bodily senses arising from concerted mechanoreception, thermoreception, proprioception, and photoreception. Untethered operation with an SLiR centipede is also demonstrated, which can execute distinct, localized body functions from directional motility, multisensing, to wireless human and environment interactions. This SLiR, which is capable of integrated perception and motility, offers new opportunities for developing diverse intelligent behaviors in soft robots.
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Affiliation(s)
- Xiao-Qiao Wang
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Kwok Hoe Chan
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Yin Cheng
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Tianpeng Ding
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Tongtao Li
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Sippanat Achavananthadith
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Selman Ahmet
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - John S Ho
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Ghim Wei Ho
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research), 3 Research Link, Singapore, 117602, Singapore
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
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167
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McCracken JM, Donovan BR, White TJ. Materials as Machines. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906564. [PMID: 32133704 DOI: 10.1002/adma.201906564] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/19/2019] [Indexed: 05/23/2023]
Abstract
Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walking, crawling, swimming, and flying). Key functional considerations of responsive materials in machine implementations are response time, cyclability (frequency and ruggedness), sizing, payload capacity, amenability to mechanical programming, performance in extreme environments, and autonomy. This review summarizes the material transformation mechanisms, mechanical design, and robotic integration of responsive materials including shape memory alloys (SMAs), piezoelectrics, dielectric elastomer actuators (DEAs), ionic electroactive polymers (IEAPs), pneumatics and hydraulics systems, shape memory polymers (SMPs), hydrogels, and liquid crystalline elastomers (LCEs) and networks (LCNs). Structural and geometrical fabrication of these materials as wires, coils, films, tubes, cones, unimorphs, bimorphs, and printed elements enables differentiated mechanical responses and consistently enables and extends functional use.
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Affiliation(s)
- Joselle M McCracken
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Brian R Donovan
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
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168
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Saed MO, Terentjev EM. Siloxane crosslinks with dynamic bond exchange enable shape programming in liquid-crystalline elastomers. Sci Rep 2020; 10:6609. [PMID: 32313059 PMCID: PMC7171139 DOI: 10.1038/s41598-020-63508-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/31/2020] [Indexed: 11/17/2022] Open
Abstract
Liquid crystalline elastomers (LCE) undergo reversible shape changes in response to stimuli, which enables a wide range of smart applications, in soft robotics, adhesive systems or biomedical medical devices. In this study, we introduce a new dynamic covalent chemistry based on siloxane equilibrium exchange into the LCE to enable processing (director alignment, remolding, and welding). Unlike the traditional siloxane based LCE, which were produced by reaction schemes with irreversible bonds (e.g. hydrosilylation), here we use a much more robust reaction (thiol-acrylate/thiol-ene 'double-click' chemistry) to obtain highly uniform dynamically crosslinked networks. Combining the siloxane crosslinker with click chemistry produces exchangeable LCE (xLCE) with tunable properties, low glass transition (-30 °C), controllable nematic to isotropic transition (33 to 70 °C), and a very high vitrification temperature (up to 250 °C). Accordingly, this class of dynamically crosslinked xLCE shows unprecedented thermal stability within the working temperature range (-50 to 140 °C), over many thermal actuation cycles without any creep. Finally, multiple xLCE sharing the same siloxane exchangeable bonds can be welded into single continuous structures to allow for composite materials that sequentially and reversibly undergo multiple phase transformations in different sections of the sample.
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Affiliation(s)
- Mohand O Saed
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
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169
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Two-Way and Multiple-Way Shape Memory Polymers for Soft Robotics: An Overview. ACTUATORS 2020. [DOI: 10.3390/act9010010] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Shape memory polymers (SMPs) are smart materials capable of changing their shapes in a predefined manner under a proper applied stimulus and have gained considerable interest in several application fields. Particularly, two-way and multiple-way SMPs offer unique opportunities to realize untethered soft robots with programmable morphology and/or properties, repeatable actuation, and advanced multi-functionalities. This review presents the recent progress of soft robots based on two-way and multiple-way thermo-responsive SMPs. All the building blocks important for the design of such robots, i.e., the base materials, manufacturing processes, working mechanisms, and modeling and simulation tools, are covered. Moreover, examples of real-world applications of soft robots and related actuators, challenges, and future directions are discussed.
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170
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Guseinov R, McMahan C, Pérez J, Daraio C, Bickel B. Programming temporal morphing of self-actuated shells. Nat Commun 2020; 11:237. [PMID: 31932589 PMCID: PMC6957700 DOI: 10.1038/s41467-019-14015-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 12/11/2019] [Indexed: 01/09/2023] Open
Abstract
Advances in shape-morphing materials, such as hydrogels, shape-memory polymers and light-responsive polymers have enabled prescribing self-directed deformations of initially flat geometries. However, most proposed solutions evolve towards a target geometry without considering time-dependent actuation paths. To achieve more complex geometries and avoid self-collisions, it is critical to encode a spatial and temporal shape evolution within the initially flat shell. Recent realizations of time-dependent morphing are limited to the actuation of few, discrete hinges and cannot form doubly curved surfaces. Here, we demonstrate a method for encoding temporal shape evolution in architected shells that assume complex shapes and doubly curved geometries. The shells are non-periodic tessellations of pre-stressed contractile unit cells that soften in water at rates prescribed locally by mesostructure geometry. The ensuing midplane contraction is coupled to the formation of encoded curvatures. We propose an inverse design tool based on a data-driven model for unit cells' temporal responses.
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Affiliation(s)
- Ruslan Guseinov
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg, 3400, Austria
| | - Connor McMahan
- California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA
| | - Jesús Pérez
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg, 3400, Austria
- Universidad Rey Juan Carlos, Calle Tulipán, s/n, Móstoles, 28933, Madrid, Spain
| | - Chiara Daraio
- California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA.
| | - Bernd Bickel
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg, 3400, Austria.
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171
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Huang X, Ford M, Patterson ZJ, Zarepoor M, Pan C, Majidi C. Shape memory materials for electrically-powered soft machines. J Mater Chem B 2020; 8:4539-4551. [DOI: 10.1039/d0tb00392a] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We review the recent progress of electrically-powered artificial muscles and soft machines using shape memory alloy and liquid crystal elastomer.
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Affiliation(s)
- Xiaonan Huang
- Soft Machines Lab
- Carnegie Mellon University
- Pittsburgh
- USA
| | - Michael Ford
- Soft Machines Lab
- Carnegie Mellon University
- Pittsburgh
- USA
| | | | - Masoud Zarepoor
- Soft Machines Lab
- Carnegie Mellon University
- Pittsburgh
- USA
- Mechanical Engineering
| | - Chengfeng Pan
- Soft Machines Lab
- Carnegie Mellon University
- Pittsburgh
- USA
| | - Carmel Majidi
- Soft Machines Lab
- Carnegie Mellon University
- Pittsburgh
- USA
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172
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Zhang C, Lu X, Fei G, Wang Z, Xia H, Zhao Y. 4D Printing of a Liquid Crystal Elastomer with a Controllable Orientation Gradient. ACS APPLIED MATERIALS & INTERFACES 2019; 11:44774-44782. [PMID: 31692319 DOI: 10.1021/acsami.9b18037] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Liquid crystal elastomers (LCEs), a class of soft materials capable of a large and reversible change in the shape under the trigger of external stimuli, can be fabricated into diverse architectures with complicated deformation modes through four-dimensional (4D) printing. However, the printable LCE ink is only in the form of monomeric precursors and the deformation mode is limited to contraction/extension deformation. Herein, we report a novel approach to break through these limitations. We achieved 4D printing of a single-component liquid crystal polymer ink in its isotropy state through direct ink writing (DIW) technology. The drawing force imposed by the movement of nozzle in the extruded printing process was able to align the mesogen units along the specific printing path. An orientation gradient perpendicular to the printing direction was obtained due to the existence of a temperature gradient between the two sides of printed samples and could be further fixed by post-photo-cross-linking treatment through the dimerizable groups in the LCE, realizing a new actuation mode in the field of extrusion-based printing of LCE actuators. The printed film was able to change reversibly from a strip to a tightly hollow cylinder and could reversibly lift up an object with roughly 600 times its own weight. The orientation gradient can be patterned through liquid-assistant printing or programmed structure design to integrate both bending and contraction actuation modes on the same printed sample, leading to complex deformation and two-dimensional (2D) planar porous structure to three-dimensional (3D) porous cylinder transition. This study opens up a new prospect to directly print a wide variety of LCE actuators with versatile actuation modes.
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Affiliation(s)
- Chun Zhang
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute , Sichuan University , Chengdu 610065 , China
| | - Xili Lu
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute , Sichuan University , Chengdu 610065 , China
| | - Guoxia Fei
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute , Sichuan University , Chengdu 610065 , China
| | - Zhanhua Wang
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute , Sichuan University , Chengdu 610065 , China
| | - Hesheng Xia
- State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute , Sichuan University , Chengdu 610065 , China
| | - Yue Zhao
- Département de chimie Université de Sherbrooke Sherbrooke , Québec J1K 2R1 , Canada
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