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Supramolecular polymer networks (SPNs) have garnered significant research interest due to their dynamic properties. However, while current developments primarily focus on managing supramolecular crosslinks, the role of polymer backbones—equally crucial to SPN properties—has not yet been sufficiently explored. Herein, we utilize mechanically interlocked [an]daisy chain as backbone to prepare a class of SPNs, where the force-induced motion of successive mechanical bonds toughens and reinforces the networks. In specific, the [an]daisy chain backbones connect with polynorbornene chains through quadruple H-bonding in the SPN networks. Compared to the control with non-slidable backbone, The representative SPN-2 exhibits a robust feature in tensile tests with high maximum stress (14.7 vs. 7.89 MPa) and toughness (83.8 vs. 48.6 MJ/m3). Moreover, it also has superior performance in energy dissipation benefitting from the [an]daisy chain backbones as well as supramolecular crosslinks. Additionally, the SPN-2 displayed exceptional self-healing and reprocessing capabilities due to their dynamic quadrable H-bonding crosslinkers. These findings demonstrate the untapped potential of [an]daisy chain as a polymer skeleton to develop SPNs and open the door to design mechanically robust supramolecular materials with diverse smart functions. [ABSTRACT FROM AUTHOR]

Architectural, compositional, and mechanical gradients are present in many interfacial tissues in the body. Yet desired for regeneration, the recreation of these complex natural gradients in porous scaffolds remains a challenging task. Additive manufacturing (AM) has been highlighted as a technology to fabricate constructs to regenerate interfacial tissues. Integration of different types of gradients, which can be physical, mechanical, and/or biochemical, shows promise to control cell fate and the regeneration process in a spatial controlled manner. One of the most studied tissue interfaces is the osteochondral unit which connects cartilage to bone. This tissue is often damaged because of trauma or ageing, leading to osteoarthritis; a degenerative disease and a major cause of disability worldwide. Therefore, in view of osteochondral (OC) regeneration, a state‐of‐the‐art overview of current approaches is presented to manufacture gradient scaffolds prepared by AM techniques. The focus is on thermoplastic, hydrogel, and hybrid scaffolds comprising gradients that induce biomimicry by their physical and biological properties. The effect of these different systems on OC tissue formation in‐vitro and in‐vivo is addressed. Finally, an outlook on current trends of dynamic materials is provided, including proposals on how these materials could improve the mimicry of scaffolds applied for OC regeneration. [ABSTRACT FROM AUTHOR]

Type I main‐chain polyrotaxanes (PRs) with multiple wheels threaded onto the axle are widely employed to design slide‐ring materials. However, Type II main‐chain PRs with axles threading into the macrocycles on the polymer backbones have rarely been studied, although they feature special topological structures and dynamic characteristics. Herein, we report the design and preparation of Type II main‐chain PR‐based mechanically interlocked networks (PRMINs), based on which the relationship between microscopic motion of mechanical bonds on the PRs and macroscopic mechanical performance of materials has been revealed. The representative PRMIN‐2 exhibits a robust feature in tensile tests with high stretchability (1680 %) and toughness (47.5 MJ/m3). Moreover, it also has good puncture performance with puncture energy of 22.0 mJ. Detailed rheological measurements and coarse‐grained molecular dynamics (CGMD) simulation reveal that the embedded multiple [2]rotaxane mechanical bonds on the PR backbones of PRMINs could undergo a synergistic long‐range sliding motion under external force, with the introduction of collective dangling chains into the network. As a result, the synchronized motions of coherent PR chains can be readily activated to accommodate network deformation and efficiently dissipate energy, thereby leading to enhanced mechanical performances of PRMINs. [ABSTRACT FROM AUTHOR]

Adhesives have been widely used to splice and repair materials to meet practical needs of humanity for thousands of years. However, developing robust adhesives with balanced adhesive and cohesive properties still remains a challenging task. Herein, we report the design and preparation of a robust mechanically interlocked [an]daisy chain network (DCMIN) adhesive by orthogonal integration of mechanical bonds and 2‐ureido‐4[1H]‐pyrimidone (UPy) H‐bonding in a single system. Specifically, the UPy moiety plays a dual role: it allows the formation of a cross‐linked network and engages in multivalent interactions with the substrate for strong interfacial bonding. The mechanically interlocked [an]daisy chain, serving as the polymeric backbone of the adhesive, is able to effectively alleviate applied stress and uphold network integrity through synergistic intramolecular motions, and thus significantly improves the cohesive performance. Comparative analysis with the control made of the same quadruple H‐bonding network but with non‐interlocked [an]daisy chain backbones demonstrates that our DCMIN possesses superior adhesion properties over a wide temperature range. These findings not only contribute to a deep understanding of the structure‐property relationship between microscopic mechanical bond motions and macroscopic adhesive properties but also provide a valuable guide for optimizing design principles of robust adhesives. [ABSTRACT FROM AUTHOR]

Supramolecular polymer networks (SPNs) are celebrated for their dynamic nature, yet they often exhibit inadequate mechanical properties. Thus far, the quest to bolster the mechanical resilience of SPNs while preserving their dynamic character presents a formidable challenge. Herein, we introduce [2]rotaxane into SPN to serve as another cross-link, which could effectively enhance the mechanical robustness of the polymer network without losing the dynamic properties. Compared with SPN, the dually cross-linked network (DPN) demonstrates superior breaking strength, Young's modulus, puncture force and toughness, underscoring its superior robustness. Furthermore, the cyclic tensile tests reveal that the energy dissipation capacity of DPN rivals, and in some cases surpasses, that of SPN, owing to the efficient energy dissipation pathway facilitated by [2]rotaxane. In addition, benefiting from stable topological structure of [2]rotaxane, DPN exhibits accelerated recovery from deformation, indicating superior elasticity compared to SPN. This strategy elevates the performance of SPNs across multiple metrics, presenting a promising avenue for the development of high-performance dynamic materials. [ABSTRACT FROM AUTHOR]

Styrene-butadiene rubber (SBR) is an indispensable material in modern society, and the necessity for enhanced mechanical properties in SBR persists, particularly to withstand the rigors of challenging environmental conditions. To surmount the limitations of conventional cross-linking modes, mechanical bonds stabilized by host-guest recognition are incorporated as the cross-linking points of SBR to form mechanically interlocked networks (MINs). Compared with covalently cross-linked network, the representative MIN exhibits superior mechanical performance in terms of elongation (1392%) and breaking strength (4.6 MPa), whose toughness has surged by 17 times. Dissociation of host-guest recognition and subsequent sliding motion provide an effective energy dissipation mechanism, and the release of hidden length is also beneficial to enhance toughness. Furthermore, the introduction of the rotaxane cross-links made the network more pliable and possess damping and elastic properties, which can return to initial state with one minute rest interval. We aspire that this direct introduction method can serve as a blueprint, offering valuable insights for the enhancement of mechanical properties in conventional commercial polymer materials. [ABSTRACT FROM AUTHOR]

Architectural, compositional, and mechanical gradients are present in many interfacial tissues in the body. Yet desired for regeneration, the recreation of these complex natural gradients in porous scaffolds remains a challenging task. Additive manufacturing (AM) has been highlighted as a technology to fabricate constructs to regenerate interfacial tissues. Integration of different types of gradients, which can be physical, mechanical, and/or biochemical, shows promise to control cell fate and the regeneration process in a spatial controlled manner. One of the most studied tissue interfaces is the osteochondral unit which connects cartilage to bone. This tissue is often damaged because of trauma or ageing, leading to osteoarthritis; a degenerative disease and a major cause of disability worldwide. Therefore, in view of osteochondral (OC) regeneration, a state‐of‐the‐art overview of current approaches is presented to manufacture gradient scaffolds prepared by AM techniques. The focus is on thermoplastic, hydrogel, and hybrid scaffolds comprising gradients that induce biomimicry by their physical and biological properties. The effect of these different systems on OC tissue formation in‐vitro and in‐vivo is addressed. Finally, an outlook on current trends of dynamic materials is provided, including proposals on how these materials could improve the mimicry of scaffolds applied for OC regeneration.

ABSTRACT: Mechanically interlocked polymers (MIPs) are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level. However, the investigations on their mechanical properties are lagging far behind their structural fabrication, especially for linear polyrotaxanes in bulk. Herein, we report stretchable poly[2]rotaxane elastomers (PREs) which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties. Specifically, we have synthesized a hydroxy-functionalized [2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs. Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane, the representative PRE exhibits favorable mechanical performance in terms of stretchability (∼1200%), Young's modulus (24.6 MPa), and toughness (49.5 MJ/m3). Moreover, we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties. It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−guest interaction and consequential sliding motion of the wheel along the axle in the [2]rotaxane motif.

Simultaneously introducing covalent and supramolecular cross‐links into one system to construct dually cross‐linked networks, has been proved an effective approach to prepare high‐performance materials. However, so far, features and advantages of dually cross‐linked networks compared with those possessing individual covalent or supramolecular cross‐linking points are rarely investigated. Herein, on the basis of comparison between supramolecular polymer network (SPN), covalent polymer network (CPN) and dually cross‐linked polymer network (DPN), we reveal that the dual cross‐linking strategy can endow the DPN with integrated advantages of CPN and SPN. Benefiting from the energy dissipative ability along with the dissociation of host–guest complexes, the DPN shows excellent toughness and ductility similar to the SPN. Meanwhile, the elasticity of covalent cross‐links in the DPN could rise the structural stability to a level comparable to the CPN, exhibiting quick deformation recovery capacity. Moreover, the DPN has the strongest breaking stress and puncture resistance among the three, proving the unique property advantages of dual cross‐linking method. These findings gained from our study further deepen the understanding of dynamic polymeric networks and facilitate the preparation of high‐performance elastomeric materials. [ABSTRACT FROM AUTHOR]

Mechanical bonds have been utilized as promising motifs to construct mechanically interlocked aerogels (MIAs) with mechanical adaptivity and multifunctionality. However, fabricating such aerogels with not only precise chemical structures but also dynamic features remains challenging. Herein, we present MIAs carrying dense [2]rotaxane units, which bestow both the stability and flexibility of the aerogel network. Owing to the stable chemical structure of a [2]rotaxane, MIAs possessing a precise and full‐scale mechanically interlocked network could be fabricated with the aid of diverse solvents. In addition, the dynamic nature of the [2]rotaxane resulted in morphologies and mechanical performances of the MIAs that can be dramatically modulated under chemical stimuli. We hope that the structure–property relationship in MIAs will facilitate the development of mechanically interlocked materials and provide novel opportunities toward constructing smart materials with multifunctionalities. [ABSTRACT FROM AUTHOR]

Supramolecular polymer networks (SPNs) demonstrate great potential in the development of smart materials owing to their attractive dynamic properties. However, as they suffer from the inherent weak bonding of most noncovalent cross‐links, it remains a significant challenge to construct SPNs with outstanding mechanical performance. Herein, we exploit the cryptand/paraquat host‐guest recognition motifs as cross‐links to prepare a class of highly strong and tough SPNs. Unlike those supramolecular cross‐links with relatively weak binding abilities, the cryptand‐based host‐guest interactions have a high association constant and steady complexing structure, which effectively stabilizes the network and resists mechanical deformation under external force. Such favorable structural stability endows our SPNs with greatly enhanced mechanical performance, compared with the control‐1 cross‐linked by the weakly complexed crown ether/secondary ammonium salt motif (tensile strength: 21.1±0.5 vs 2.8±0.1 MPa; Young's modulus: 102.6±4.8 vs 2.1±0.3 MPa; toughness: 90.4±2.0 vs 10.8±0.6 MJ m−3). Moreover, our SPNs also retain abundant dynamic properties including good abilities in energy dissipation, reprocessability, and stimuli‐responsiveness. These findings provide novel insights into the preparation of SPNs with enhanced mechanical properties, and promote the development of high‐performance intelligent supramolecular materials. [ABSTRACT FROM AUTHOR]

The transient self‐assembly of molecules under the direction of a consumable fuel source is fundamental to biological processes such as cellular organization and motility. Such biomolecular assemblies exist in an out‐of‐equilibrium state, requiring continuous consumption of high energy molecules. At the same time, the creation of bioinspired supramolecular hydrogels has traditionally focused on associations occurring at the thermodynamic equilibrium state. Here, hydrogels are prepared from cucurbit[7]uril host–guest supramolecular interactions through transient physical crosslinking driven by the consumption of a reactive chemical fuel. Upon action from this fuel, the affinity and dynamics of CB[7]–guest recognition are altered. In this way, the lifetime of transient hydrogel formation and the dynamic modulus obtained are governed by fuel consumption, rather than being directed by equilibrium complex formation. [ABSTRACT FROM AUTHOR]

Crosslinking plays a crucial role in determining mechanical properties of polymer materials. Although various crosslinks based on covalent or noncovalent bonds have been adopted, it remains an enormous challenge to develop a crosslink which could endow corresponding polymer network with robust yet dynamic properties. Herein, we report a crosslink simultaneously having dynamic property and woven geometry, and the polymer network with woven crosslinks (WPN) could integrate the merits of covalent polymer network (CPN) and supramolecular polymer network (SPN). In specific, the WPN not only exhibits comparable stiffness, strength, elastic recovery, and anti‐fatigue property to those of CPN, but also possesses decent mechanical adaptivity and ductility, similar to those of SPN. Particularly, its toughness and puncture resistance are much superior to those of the others. Besides, the dynamicity of woven crosslink also imparts good performances of self‐healing and processability to WPN. [ABSTRACT FROM AUTHOR]

Granular biomaterials have found widespread applications in tissue engineering, in part because of their inherent porosity, tunable properties, injectability, and 3D printability. However, the assembly of granular hydrogels typically relies on spherical microparticles and more complex particle geometries have been limited in scope, often requiring templating of individual microgels by microfluidics or in-mold polymerization. Here, we use dithiolane-functionalized synthetic macromolecules to fabricate photopolymerized microgels via batch emulsion, and then harness the dynamic disulfide crosslinks to rearrange the network. Through unconfined compression between parallel plates in the presence of photoinitiated radicals, we transform the isotropic microgels are transformed into disks. Characterizing this process, we find that the areas of the microgel surface in contact with the compressive plates are flattened while the curvature of the uncompressed microgel boundaries increases. When cultured with C2C12 myoblasts, cells localize to regions of higher curvature on the disk-shaped microgel surfaces. This altered localization affects cell-driven construction of large supraparticle scaffold assemblies, with spherical particles assembling without specific junction structure while disk microgels assemble preferentially on their curved surfaces. These results represent a unique spatiotemporal process for rapid reprocessing of microgels into anisotropic shapes, providing new opportunities to study shape-driven mechanobiological cues during and after granular hydrogel assembly., (© 2023 Wiley‐VCH GmbH.)

Abstract Topological metamorphosis represents a powerful approach to modulate the properties of polymers. However, it still remains a major challenge to achieve the tunability of bulk mechanical properties via topological transformation in supramolecular polymer systems. Herein, we couple the covalent polymer and supramolecular polymer in a single system—referred to as covalent‐and‐supramolecular polymer (CSP)—to realize a thermo‐responsive macromolecular metamorphosis. The CSP is able to topologically switch from grafted polymer to cross‐linked network by taking advantage of synergistic dynamic covalent interactions and host–guest interactions. Benefiting from the topologically structural transformation, brittleness intrinsically evolves into toughness in our CSP architectures with minimum change of their molecular compositions from furan–maleimide to anthracene–maleimide linkers. Our work demonstrates that supramolecular polymers are a promising platform to design smart materials not only due to their inherent stimuli‐responsive properties but also because of their abilities in determining bulk mechanical properties of polymers with alterable topological structures.

Dynamic materials (DMs) or dynamers have potential applications across a broad range of material science challenges. These applications include sustainable materials as a part of the circular plastics economy, advanced materials with tailored high stress properties and biomedical agents. DMs are comprised of polymers that crosslinked through reversible covalent and noncovalent linking groups. This group provides reversible bonds, which impart properties such as (re)healing, adaptability, toughness into a material. The nature of the linker dictates the dynamer's stability and dynamic properties, although for many applications one linker alone cannot give materials with complex multiresponsive functions. The combination of multiple dynamic linkers can introduce complementary functionalities into a single material. This combination of linkers enhances the collective material properties by matching their strengths and offsetting the weaknesses, or by selecting linkers for specific functions, such as one linker for rapid exchange and the other to respond to external stimuli. This contribution highlights the possibilities and unique features of materials containing multiple dynamic linkers, reviewing both fundamental discoveries of materials possessing multiple dynamic bonds and applications facilitated by the presence of multiple linking group chemistry. [ABSTRACT FROM AUTHOR]

Gas molecules, as a family of unique polyatomic building blocks, have long been considered hard to involve in molecular assembly or construct assembled materials due to their structural simplicity yet paucity of defined interacting sites. To solve this non-trivial challenge, a core idea is to break the limit of current ways of bonding gas molecules, endowing them with new modes of interactions that match the basic requirements of molecular assembly. In recent years, a new concept, named the dynamic gas-bridged bond (DGB), has emerged, which allows for gas molecules to constitute a dynamic bridging structure between other building blocks with the aid of frustrated Lewis pairs. This makes it possible to harness gas in a supramolecular or dynamic manner. Herein, this perspective discusses distinct dynamic natures of DGBs and manifests their particular functions in various fields, including the control of molecular/polymeric self-assembly nanostructures, creation of multidimensional assembled materials, and recyclable catalysts. The future research direction and challenges of dynamic gas-bridged chemistry toward gas-programmed self-assembly and gas-constructed adaptive materials are highlighted.

[Display omitted] • Simple building blocks enable orthogonal solvent-free coupling of DCBs. • Poly(TABA) shows relatively high mechanical robustness (E = 1.1 GPa, σ t = 30 MPa). • Rheological kinetic analysis reveals intrinsic temperature range of bond exchange. • A fluorescent and shape-memorable dual-encryption material is constructed by design. • Multi-ways (decrosslinking and depolymerization) employed to recycle this material. Replacing the "inert" chemical bonds in traditional materials with dynamic bonds brings opportunities in designing renewable materials that repair, reprocess and recycle. Despite the many efforts made in covalent adaptable networks by elaborating a single type of dynamic covalent chemistry, the fabrication of double dynamic covalent polymeric networks, especially using simple small-molecule building blocks, still remains challenging. Here we report the solvent-free construction of a thermosetting material by combining 1,2-dithiolane-based reversible polymerization and dynamic covalent boroxine chemistry as crosslinkers. The resulting materials exhibit tunable mechanical properties, mechanical reprocessability, shape memory ability and closed-loop chemical recyclability. Quantitative kinetic analysis reveals the temperature-dependent apparent activation energy for the bond exchange of the resulting network as a result of the simultaneous integration of the two dynamic covalent bonds. Meanwhile, the boroxine units also act as a luminescent center to enable an emissive "organic glass" that can be used as a dual encryption material taking advantage of the reprogrammable shape-memory behavior of the dynamic network. Benefitting from the simple design, tunable variables and multi-functions, we envision that this double dynamic chemistry offers a robust scaffold and great chemical spaces for the design of dynamic polymeric materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dynamic Ir electronic and geometric structural change with surface adsorption. • pH-dependent oxygenate adsorption and Ir dissolution pathway. • Unfavorable adsorption coincides with distorted Ir linkage and decreased Ir valence state. The interaction between catalyst surfaces and adsorbed oxygen intermediates is critical to catalytic performance for electrochemical water oxidation to oxygen. However, the relationship between adsorption energetics and electrocatalytic activity is primarily assessed for pristine catalyst materials, which leaves much unknown about the dynamics of these properties in relationship to catalyst performance during long-term operation. In this work, we experimentally assess OH and O adsorption on Ca 2 IrO 4 nanoparticles and monitor their evolution during extensive chronoamperometry tests at highly oxidizing potentials in a range of low pH electrolytes. In situ x-ray absorption spectroscopy reveals changes for surface adsorbate energetics and local iridium structures with applied potentials. Increasingly unfavorable adsorption of OH and formation of O intermediates after long-term operation is correlated with severe metal dissolution, distorted [IrO 6 ] octahedral linkages, and a decreased average Ir valence. This work establishes connections between surface adsorption energetics, Ir structure, OER kinetics, and material stability outcomes. [ABSTRACT FROM AUTHOR]

The paper reports new chitosan-based nanofibers, designed to address the healing of burn wounds. To this aim, mesoporous chitosan fiber mats were prepared by electrospinning using poly(ethylene oxide) as sacrificial additive, followed by loading with norfloxacin and coating with an antifungal agent via dynamic imine bonds. Dynamic vapor sorption experiment proved intra-fiber mesopores around 2.7 nm, and UV–vis, FTIR, and NMR spectroscopy confirmed the norfloxacin embedding and the imination reaction. SEM, AFM and POM techniques displayed semicrystalline nanofibers with average diameter around 170 nm entangled into a non-woven mat. Their mesoporous nature favored a rapid adsorption of fluids up to 17 g/g, and a biodegradation rate fitting the wound healing rate, i.e. up to 30 % mass loss in media of pH characteristic to wound exudate and total degradation in that characteristic to normal dermis. The composite fibers released the NFX and 2FPBA in a controlled manner, and showed antimicrobial activity against gram positive, gram negative and fungal strains. They had no cytotoxic effect on normal human dermal fibroblasts, and showed biocompatibility on experimental rats. The investigation of wound healing ability on second/third-degree burn model in rats revealed wound closure and total restoration of the fully functional dermis and epidermis. [Display omitted] [ABSTRACT FROM AUTHOR]

Like any other thermosetting material, polyurethane foams (PUFs) contain permanent cross-links that hinder their reprocessability and make their recyclability a tedious and environmentally unfriendly process. Herein, we introduce acetoacetyl-formed amides, formed by the reaction of isocyanates with acetoacetate groups, as dynamic units in the backbone of PUFs. By extensive variation of the foam composition, optimum parameters have been found to produce malleable foams above temperatures of 130 °C, without the requirement of any solvent during the foaming process. The PU cross-linked material can be compression-molded at least three times, giving rise to PU elastomers and thus maintaining a cross-linked network structure. Characterization of the original foams shows comparable properties to standard PUFs, for example, having a density of 32 kg/m 3 , while they show similar chemical and thermal properties upon reprocessing to strong PU elastomers, exhibiting T g ranging from -42 to -48 °C. This research provides a straightforward method to produce thermally reprocessable PUFs as a promising pathway to address the recycling issues of end-of-life foams.

The temporary nature of this fuel-directed change in the interacting molecules causes the gels that are formed from this fuel to have a limited lifetime, autonomously converting back to their original pre-gel state over time without additional user input. Inside Back Cover: Transient and Dissipative Host-Guest Hydrogels Regulated by Consumption of a Reactive Chemical Fuel (Angew. Keywords: Chemical Fuel; Dynamic Materials; Non-Equilibrium; Rheology; Soft Matter EN Chemical Fuel Dynamic Materials Non-Equilibrium Rheology Soft Matter 1 1 1 03/02/23 20230306 NES 230306 B A new route to prepare hydrogels b relies on consumption of a chemical fuel to transiently drive network crosslinking by host-guest motifs, thereby prompting hydrogelation. [Extracted from the article]

The temporary nature of this fuel-directed change in the interacting molecules causes the gels that are formed from this fuel to have a limited lifetime, autonomously converting back to their original pre-gel state over time without additional user input. Keywords: Chemical Fuel; Dynamic Materials; Non-Equilibrium; Rheology; Soft Matter EN Chemical Fuel Dynamic Materials Non-Equilibrium Rheology Soft Matter 1 1 1 03/02/23 20230306 NES 230306 B A new route to prepare hydrogels b relies on consumption of a chemical fuel to transiently drive network crosslinking by host-guest motifs, thereby prompting hydrogelation. Chemical Fuel, Dynamic Materials, Non-Equilibrium, Rheology, Soft Matter. [Extracted from the article]

Mechanically interlocked polymers (MIPs) are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level. However, the investigations on their mechanical properties are lagging far behind their structural fabrication, especially for linear polyrotaxanes in bulk. Herein, we report stretchable poly[2]rotaxane elastomers (PREs) which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties. Specifically, we have synthesized a hydroxy-functionalized [2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs. Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane, the representative PRE exhibits favorable mechanical performance in terms of stretchability (∼1200%), Young's modulus (24.6 MPa), and toughness (49.5 MJ/m 3 ). Moreover, we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties. It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host-guest interaction and consequential sliding motion of the wheel along the axle in the [2]rotaxane motif., Competing Interests: The authors declare that they have no conflicts of interest in this work., (© 2022 The Authors. Publishing Services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.)