51
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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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Ma J, Yang Y, Valenzuela C, Zhang X, Wang L, Feng W. Mechanochromic, Shape-Programmable and Self-Healable Cholesteric Liquid Crystal Elastomers Enabled by Dynamic Covalent Boronic Ester Bonds. Angew Chem Int Ed Engl 2021; 61:e202116219. [PMID: 34962037 DOI: 10.1002/anie.202116219] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Indexed: 11/08/2022]
Abstract
Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape-programmable and self-healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main-chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self-healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next-generation intelligent machines.
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Affiliation(s)
- Jiazhe Ma
- Tianjin University, Materials Science & Engineering, CHINA
| | - Yanzhao Yang
- Tianjin University, Materials Science & Engineering, CHINA
| | | | - Xuan Zhang
- Tianjin University, Materials Science & Engineering, CHINA
| | - Ling Wang
- Tianjin University, Materials Science & Engineering, School of Materials Science and Engineering, Tianjin University, 300072, Tianjin, CHINA
| | - Wei Feng
- Tianjin University, Materials Science & Engineering, CHINA
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Saed M, Lin X, Terentjev EM. Dynamic Semicrystalline Networks of Polypropylene with Thiol-Anhydride Exchangeable Crosslinks. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42044-42051. [PMID: 34437806 PMCID: PMC8431344 DOI: 10.1021/acsami.1c12099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Thermoplastic polyolefins (TPOs) crosslinked by dynamic covalent bonds (xTPOs) have the potential to be the most utilized class of polymer in the world, with applications ranging from household and automotive to biomedical devices and additive manufacturing. xTPO combines the benefits of thermoplastics and thermosets in a "single material" and potentially avoids their shortcomings. Here, we describe a new two-stage reaction extrusion strategy of TPOs with a backbone consisting of inert C-C bonds (polypropylene, PP), and thiol-anhydride, to dynamically crosslink PP through thiol-thioester bond exchange. The degree of PP crosslinking determines the rubber plateau modulus above the melting point of the plastic: the modulus at 200 °C increases from zero in the melt to 23 kPa at 6% crosslinking, to 60 kPa at 20%, to 105 kPa at 40%. The overall mechanical strength of the solid xTPO plastic is 25% higher compared to the original PP, and the gel fraction of xTPO reaches 55%. Finally, we demonstrate that the crosslinked xTPO material is readily reprocessable (recycled, remolded, rewelded, and 3D printed).
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Huang S, Shen Y, Bisoyi HK, Tao Y, Liu Z, Wang M, Yang H, Li Q. Covalent Adaptable Liquid Crystal Networks Enabled by Reversible Ring-Opening Cascades of Cyclic Disulfides. J Am Chem Soc 2021; 143:12543-12551. [PMID: 34275290 DOI: 10.1021/jacs.1c03661] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of covalent adaptable liquid crystal networks (LCNs) enabled by introducing dynamic covalent bonds has endowed liquid crystal actuators with self-healing properties and reversible shape programmability, broadening their applications in diverse soft robotic devices. However, the finite molecular design strategy limits the recyclability and the architectural diversity of these materials. Here, a strategy is first reported for fabricating photoresponsive polydisulfide-based covalent adaptable LCNs by ring-opening polymerization of cyclic dithiolane groups. Based on the disulfide metathesis, the resulting materials are self-healable, reshapable, and reprogrammable. Importantly, the equilibrium between the polymer backbones and the dithiolane-functionalized monomers enables catalytic depolymerization to recycle monomers, which could significantly weaken the disadvantage of subtractive manufacturing of photomechanical devices. This work rooted in chemistry would provide an economical and environmentally friendly strategy for the fabrication of functional soft robotics with excellent programmability and renewability and beyond.
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Affiliation(s)
- Shuai Huang
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Yikang Shen
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Hari K Bisoyi
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
| | - Yu Tao
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Zhongcheng Liu
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Meng Wang
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Hong Yang
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
| | - Quan Li
- Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China.,Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
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