Supramolecular polymers at work

Bosman, Anton W.; Sijbesma, RP Rint; Meijer, E. W.

doi:10.1016/s1369-7021(04)00187-7

Cited by 251 publications

(184 citation statements)

References 5 publications

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“…The ability to vary and control the interactions in supramolecular systems provides an efficient tool to tune the structure, dynamics and rheology [26,29,46].…”

Section: Introductionmentioning

confidence: 99%

Linear shear and nonlinear extensional rheology of unentangled supramolecular side-chain polymers

Cui

Boudara

Huang

et al. 2018

Journal of Rheology

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Supramolecular polymers are important within a wide range of applications including printing, adhesives, coatings, cosmetics, surgery and nano-fabrication. The possibility to tune polymer properties through the control of supramolecular associations makes these materials both versatile and powerful. Here, we present a systematic investigation of the linear shear rheology for a series of unentangled ethylhexyl acrylate based polymers for which the concentration of randomly distributed supramolecular side-groups are systematically varied. We perform a detailed investigation of the appplicability of Time Temperature Superposition (TTS) for our polymers; small amplitude oscillatory shear rheology is combined with stress relaxation experiments to identify the dynamic range over which TTS is a reasonable approximation. Moreover, we find that the "stickyRouse" model normally used to interpret the rheological response of supramolecular polymers fits our experimental data well in the terminal regime, but is less successful in the rubbery plateau regime. We propose some modifications to the "sticky-Rouse" model, which includes more realistic assumptions with regards to (i) the random placement of the stickers along the backbone, (ii) the contributions from dangling chain ends and (iii) the chain motion upon dissociation of a sticker and re-association with a new co-ordination which involves a finite sized "hop" of the chain. Our model provides an improved description of the plateau region. Finally, we measure the extensional rheological response of one of our supramolecular polymers. For the probed extensional flow rates, which are small compared to the characteristic rates of sticker dynamics, we expect a Rouse-type description to work well. We test this by modeling the observed strain hardening using the upper convected Maxwell model and demonstrate that this simple model can describe the data well, confirming the prediction and supporting our determination of sticker dynamics based on linear shear rheology. * k.j.l.mattsson@leeds.ac.uk 2

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“…The ability to vary and control the interactions in supramolecular systems provides an efficient tool to tune the structure, dynamics and rheology [26,29,46].…”

Section: Introductionmentioning

confidence: 99%

Linear shear and nonlinear extensional rheology of unentangled supramolecular side-chain polymers

Cui

Boudara

Huang

et al. 2018

Journal of Rheology

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“…10,[18][19][20][21] Its synthetic accessibility, and the ease with which small molecules [22][23][24] as well as telechelic polymers, 20,25,26 e.g., poly-(ethylene butylene) (PEB), 18,27 can be functionalized with UPy moieties to form supramolecular polymers with a wide range of properties, promise to enable the transformation of supramolecular polymers from a scientific curiosity to a concept with a wide range of practical applications. 5 The growth of applications of UPy-based supramolecular polymers further enhances the importance of a thorough understanding of the relation between chemical structure and mechanical properties of supramolecular polymers. In the past, we have emphasized the importance of unidirectionality of hydrogen bonding in order to establish supramolecular polymers as a class of materials directly analogous to linear covalent polymers.…”

Section: Introductionmentioning

confidence: 99%

Unidirectional Dimerization and Stacking of Ureidopyrimidinone End Groups in Polycaprolactone Supramolecular Polymers

et al. 2007

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The effect of stacking of end groups on the rheological behavior of supramolecular polymer melts is reported. Oscillatory shear experiments in the transition zone from the pseudo rubber plateau to the flow region of telechelic polycaprolactones (PCLs) with ureidopyrimidinone (UPy) end groups directly attached to PCL can be fitted with a single Maxwell element. This demonstrates that dimerization of the UPy groups is unidirectional and that reversible chain scission is faster than reptation. If the UPy groups are connected to the polymer via a urethane linker, a low-frequency plateau in G′ is observed. This is ascribed to the formation of a network of stacked UPy dimers, aided by urethane hydrogen bonding. Below their melting point, these stacks form long fibers in the urethane linked supramolecular poly(methyl caprolactone), which were observed with atomic force microscopy (AFM). Steric hindrance interferes with stacking, since the plateau in G′ is lower in a urethane linked polymer with bulky adamantyl-UPy end groups.

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“…1a) should be especially well suited for this purpose, because such morphologies generally bestow the material with high toughness. The supramolecular motifs can disengage in the solid state on exposure to heat or a competitive binding agent 12,13 , causing disassembly into small molecules 14 and viscosity reductions. Reporting a series of supramolecular materials formed by metal-ligand interactions, we demonstrate here that this architecture is an excellent basis for elastomeric materials in which defects can be efficiently repaired.…”

mentioning

confidence: 99%

Optically healable supramolecular polymers

Burnworth

Tang

Kumpfer

et al. 2011

Nature

1,591

1,327

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Polymers with the ability to repair themselves after sustaining damage could extend the lifetimes of materials used in many applications 1 . Most approaches to healable materials require heating the damaged area [2][3][4] . Here we present metallosupramolecular polymers that can be mended through exposure to light. They consist of telechelic, rubbery, low-molecular-mass polymers with ligand end groups that are non-covalently linked through metal-ion binding. On exposure to ultraviolet light, the metal-ligand motifs are electronically excited and the absorbed energy is converted into heat. This causes temporary disengagement of the metal-ligand motifs and a concomitant reversible decrease in the polymers' molecular mass and viscosity 5 , thereby allowing quick and efficient defect healing. Light can be applied locally to a damage site, so objects can in principle be healed under load. We anticipate that this approach to healable materials, based on supramolecular polymers and a light-heat conversion step, can be applied to a wide range of supramolecular materials that use different chemistries.The healing of cracks in amorphous polymers by heating above the glass transition temperature (T g ) involves surface rearrangement and approach of polymer chains, followed by wetting, diffusion and reentanglement of the chains 6 . Because the rates of the final two steps are inversely proportional to the molecular mass, healing is generally slow and inefficient. This problem can be overcome by exploiting thermally reversible, covalent bonds 7,8 or non-covalent supramolecular motifs 5,9,10 that allow the reaction equilibrium to be temporarily shifted to lower-molecular-mass species 11 on exposure to heat. This reduces the viscosity of the material, such that defects can be mended, before the equilibrium is shifted back and the polymer is reformed. Supramolecular polymers that phase separate into physically crosslinked networks (Fig. 1a) should be especially well suited for this purpose, because such morphologies generally bestow the material with high toughness. The supramolecular motifs can disengage in the solid state on exposure to heat or a competitive binding agent 12,13 , causing disassembly into small molecules 14 and viscosity reductions. Reporting a series of supramolecular materials formed by metal-ligand interactions, we demonstrate here that this architecture is an excellent basis for elastomeric materials in which defects can be efficiently repaired. We show that the use of light 15 as a stimulus for the dissociation of supramolecular motifs has distinct advantages over thermally healable systems, including the possibility of exclusively exposing and healing the damaged region.The new polymers are based on a macromonomer comprising a rubbery, amorphous poly(ethylene-co-butylene) core with 2,6-bis(19-methylbenzimidazolyl)pyridine (Mebip) ligands at the termini (Fig. 1b, 3). This design was based on the assumption that the hydrophobic core and the polar metal-ligand motif would phase separate 16 . Metal-Mebip com...

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Supramolecular polymers at work

Cited by 251 publications

References 5 publications

Linear shear and nonlinear extensional rheology of unentangled supramolecular side-chain polymers

Linear shear and nonlinear extensional rheology of unentangled supramolecular side-chain polymers

Unidirectional Dimerization and Stacking of Ureidopyrimidinone End Groups in Polycaprolactone Supramolecular Polymers

Optically healable supramolecular polymers

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