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Chemical composition and architecture are two key factors that control the physical and material properties of polymers. Some of the more unusual and intriguing polymer architectures are the polycatenanes, which are a class of polymers that contain mechanically interlocked rings. Since the development of high yielding synthetic routes to catenanes, there has been an interest in accessing their polymeric counterparts, primarily on account of the unique conformations and degrees of freedom offered by non-bonded interlocked rings. This has lead to the synthesis of a wide variety of polycatenane architectures and to studies aimed at developing structure–property relationships of these interesting materials. In this review, we provide an overview of the field of polycatenanes, exploring synthesis, architecture, properties, simulation, and modelling, with a specific focus on some of the more recent developments.
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Material properties and applications of mechanically interlocked polymers
Mechanically interlocked polymers (MIPs), polymer architectures that incorporate the mechanical bond, have seen a dramatic growth in interest over the last decade or so. Of particular interest in these architectures are the high mobility and conformational freedom of the interlocked components, which can give rise to unique property profiles. Over the years the research advances, from the chemistry, physics, material science and engineering fields, has started to build an understanding of how incorporating mechanical bonds into a polymer structure impacts its properties. This review focuses on summarizing the state-of-the-art understanding of the structure-property relationships in these materials and an outlook toward their applications, specifically focusing on four main classes of MIPs, polyrotaxanes, slide-ring gels, daisy-chain polymers and polycatenanes.
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- Award ID(s):
- 1903603
- PAR ID:
- 10232650
- Date Published:
- Journal Name:
- Nature Reviews Materials
- ISSN:
- 2058-8437
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The integration of mechanically interlocked molecules (MIMs) into polymeric materials has led to the development of mechanically interlocked polymers (MIPs). One class of MIPs that have gained attention in recent years are slide‐ring gels (SRGs), which are generally accessed by crosslinking rings on a main‐chain polyrotaxane. The mobility of the interlocked crosslinking moieties along the polymer backbone imparts enhanced properties onto these networks. An alternative synthetic approach to SRGs is to use a doubly threaded ring as the crosslinking moiety, yielding doubly threaded slide‐ring gel networks (dt‐SRGs). In this study, a photo‐curable ligand‐containing thread was used to assemble a series of metal‐templated pseudo[3]rotaxane crosslinkers that allow access to polymer networks that contain doubly threaded interlocked rings. The physicochemical and mechanical properties of these dt‐SRGs with varying size of the ring crosslinking moieties were investigated and compared to an entangled gel (EG) prepared by polymerizing the metal complex of the photo‐curable ligand‐containing thread, and a corresponding covalent gel (CG). Relative to the EG and CG, the dt‐SRGs exhibit enhanced swelling behavior, viscoelastic properties, and stress relaxation characteristics. In addition, the macroscopic properties of dt‐SRGs could be altered by “locking” ring mobility in the structure through remetalation, highlighting the impact of the mobility of the crosslinks.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41578-021-00278-z
