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Qiu W, He X, Fang Z, Wang Y, Dong K, Zhang G, Xu X, Ge Q, Xiong Y. Shape-Tunable 4D Printing of LCEs via Cooling Rate Modulation: Stimulus-Free Locking of Actuated State at Room Temperature. ACS Appl Mater Interfaces 2023; 15:47509-47519. [PMID: 37769329 DOI: 10.1021/acsami.3c10210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Liquid crystal elastomers (LCEs) have garnered considerable attention in the field of four-dimensional (4D) printing due to their large, reversible, and anisotropic shape-morphing capabilities. By utilizing direct ink writing, intricate LCE structures with programmable shape morphing can be achieved. However, the maintenance of the actuated state for LCEs requires continuous and substantial external stimuli, presenting challenges for practical applications, particularly under ambient conditions. This study reports a straightforward and effective physical approach to lock the actuated state of LCEs through rapid cooling while preserving their reversible performance. Rapid cooling significantly reduces the mobility of the lightly cross-linked network in LCEs, resulting in a notably slow recovery of mesogen alignment. As a result, the locked LCE structures retain their actuated state even at room temperature. Moreover, we demonstrate the ability to achieve tunable shapes between the original and actuated states by modulating the cooling rate, i.e., varying the temperature and type of cooling medium. The proposed method opens up new possibilities to achieve stable and tunable shape locking of soft devices for engineering applications.
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Affiliation(s)
- Wanglin Qiu
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Xiangnan He
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Zeming Fang
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Yaohui Wang
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Ke Dong
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Guoquan Zhang
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Xuguang Xu
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Qi Ge
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Yi Xiong
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen 518055, P. R. China
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Zhong Y, Tang W, Xu H, Qin K, Yan D, Fan X, Qu Y, Li Z, Jiao Z, Yang H, Zou J. Phase-transforming mechanical metamaterials with dynamically controllable shape-locking performance. Natl Sci Rev 2023; 10:nwad192. [PMID: 37565196 PMCID: PMC10411672 DOI: 10.1093/nsr/nwad192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 06/24/2023] [Accepted: 06/30/2023] [Indexed: 08/12/2023] Open
Abstract
Active mechanical metamaterials with customizable structures and deformations, active reversible deformation, dynamically controllable shape-locking performance and stretchability are highly suitable for applications in soft robotics and flexible electronics, yet it is challenging to integrate them due to their mutual conflicts. Here, we introduce a class of phase-transforming mechanical metamaterials (PMMs) that integrate the above properties. Periodically arranging basic actuating units according to the designed pattern configuration and positional relationship, PMMs can customize complex and diverse structures and deformations. Liquid-vapor phase transformation provides active reversible large deformation while a silicone matrix offers stretchability. The contained carbonyl iron powder endows PMMs with dynamically controllable shape-locking performance, thereby achieving magnetically assisted shape locking and energy storing in different working modes. We build a theoretical model and finite element simulation to guide the design process of PMMs, so as to develop a variety of PMMs with different functions suitable for different applications, such as a programmed PMM, reconfigurable antenna, soft lens, soft mechanical memory, biomimetic hand, biomimetic flytrap and self-contained soft gripper. PMMs are applicable to achieve various 2D deformations and 2D-to-3D deformations, and integrate multiple properties, including customizable structures and deformations, active reversible deformation, rapid reversible shape locking, adjustable energy storing and stretchability, which could open a new application avenue in soft robotics and flexible electronics.
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Affiliation(s)
- Yiding Zhong
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wei Tang
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China
| | - Huxiu Xu
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Kecheng Qin
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Dong Yan
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xujun Fan
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yang Qu
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhaoyang Li
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhongdong Jiao
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Huayong Yang
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jun Zou
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China
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Wu Y, Su C, Wang S, Zheng B, Mahjoubnia A, Sattari K, Zhang H, Meister J, Huang G, Lin J. A Photocured Bio-based Shape Memory Thermoplastics for Reversible Wet Adhesion. Chem Eng J 2023; 470:144226. [PMID: 37484781 PMCID: PMC10361415 DOI: 10.1016/j.cej.2023.144226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Development of reversible wet or underwater adhesives remains a grand challenge. Because weakened intermolecular interactions by water molecules or/and low effective contact area cause poor interface to the wet surfaces, which significantly decreases adhesive strength. Herein, a new photocured, bio-based shape memory polymer (SMP) that shows both chemical and structural wet adhesion to various types of surfaces is developed. The SMP is polymerized from three monomers mainly from bio-sources to form linear polymer chains dangled with hydrophobic side chains. The hydrogen acceptor and donor groups in the chains form hydrogen bonding with the surfaces, which is protected by the hydrophobic chains in the interface. The SMP shows tunable phase transition temperature (Tg) of 17-38 °C. In a rubbery state above Tg, the adhesive forms conformable contact with the targeted surfaces. Below Tg, a transition to a glassy state locks the conformed shapes to largely increase the effective contact area. As a result, the adhesive exhibits long-term underwater adhesion of > 15 days with the best adhesion strength of ~ 0.9 MPa. Its applications in leak repair, underwater on-skin sensors were demonstrated. This new, general strategy would pave avenues to designing bio-based, long-lasting, and reversible adhesives from renewable feedstocks for widespread applications.
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Affiliation(s)
- Yuchao Wu
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Changhua Su
- Food Science Program, Division of Food, Nutrition & Exercise Sciences; University of Missouri, Columbia, Missouri 65211, USA
| | - Shaoyun Wang
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Bujingda Zheng
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Alireza Mahjoubnia
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Kianoosh Sattari
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Hanwen Zhang
- Department of Chemical Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - James Meister
- Department of Civil and Environmental Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Guoliang Huang
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
| | - Jian Lin
- Department of Mechanical and Aerospace Engineering; University of Missouri, Columbia, Missouri 65211, USA
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Abstract
Soft adhesion is capable of attaching and bonding to rough surfaces and gripping nonplanar materials. It is preferable for material handling applications where safe interactions with external environments and enhanced adaptability to changing conditions are required. Soft electroadhesion (EA) is an emerging controllable adhesion technology that is especially suited to soft adhesion applications, but is prone to contact peeling that causes unwanted de-adhesion and cannot lift heavy objects unless the lifting force is applied parallel to the surface. Variable stiffness electroadhesion (VSEA) can be used to overcome these issues. Here a VSEA solution is developed by integrating electrostatic layer jamming and soft EA into a monolithic electrically controllable structure. The VSEA pad can achieve rapid response (within 1 s) and significant stiffness change (2200%), resist over four times the peeling force under a weight of 70 g, and generate 24.2%, 34.8%, and 49.3% greater adhesive forces on flat, convex, and concave surfaces, respectively. The promising gripping performance of the VSEA gripper was demonstrated by lifting and moving curved and flat objects. The VSEA concept and solution shown in this work may pave the way for the ready integration of EA into soft robotic systems and promote the broad application of EA technologies.
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Affiliation(s)
- Rui Chen
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing, China
| | - Zhuo Zhang
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing, China
| | - Jianglong Guo
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, China
| | - Fuyou Liu
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing, China
| | - Jinsong Leng
- Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin, China
| | - Jonathan Rossiter
- SoftLab, Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
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Abstract
Soft robots leverage deformable bodies to achieve different types of locomotion, improve transportability, and safely navigate cluttered environments. In this context, variable-stiffness structures provide soft robots with additional properties, such as the ability to increase forces transmitted to the environment, to lock into different body configurations, and to reduce the number of actuators required for morphological change. Tensegrity structures have been recently proposed as a biologically inspired design principle for soft robots. However, the few examples of tensegrity structures with variable stiffness displayed relatively small stiffness change (i.e., by a factor of 3) or resorted to multiple and bulky actuators. In this article, we describe a novel design approach to variable-stiffness tensegrity structures (VSTSs) that relies on the use of variable-stiffness cables (VSCs). As an example, we describe the design and implementation of a three-strut tensegrity structure with VSCs made of low melting point alloys. The resulting VSTS displays unprecedented stiffness changes by a factor of 28 in compression and 13 in bending. We show the capabilities of the proposed VSTS in three validation scenarios with different tensegrity architectures: (1) a beam with tunable load-bearing capability, (2) a structure that can self-deploy and lock its shape in both deployed and undeployed states, and (3) a joint with underactuated shape deformations.
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Affiliation(s)
- Davide Zappetti
- Institute of Microengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Seung Hee Jeong
- Institute of Microengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jun Shintake
- Institute of Microengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Mechanical and Intelligent Systems Engineering, School of Informatics and Engineering, University of Electro-Communications, Chofu, Japan
| | - Dario Floreano
- Institute of Microengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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