New Insights on the Self‐Organization of PEG/α‐Cyclodextrin‐Based Polyrotaxanes in Solution: An Experimental and Theoretical Study

Peña-Bahamonde, Janire; Atencia, José Joaquín; Pozuelo, Javier; Tarazona, M. Pilar; Mendicuti, Francisco

doi:10.1002/macp.201300370

Cited by 4 publications

(7 citation statements)

References 75 publications

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“…The stiffening of these molecules has recently been studied by Pinson et al using an exactly solvable theoretical model . On the other hand, experiments have shown that hairpin conformations are possible as well in free polyrotaxane molecules, if their rotor density remains significantly below the saturation density …”

Section: Introductionmentioning

confidence: 99%

“…While in the case of ordinary bottle brushes such a breakup would lead to the creation of only two fragments, − a grafted polyrotaxane releases a large number of its rotors into the environment. Such a complex could therefore qualify as a drug-delivery system. , …”

Section: Introductionmentioning

confidence: 99%

“…These differences are a consequence of the “spillover” of the polymer brush at the two backbone ends, and they diminish asymptotically toward the limit of very long backbones or comparably short chain lengths of the grafted polymers. ,, Yet, the additional degree of freedom of sliding components appears to alter the viscoelastic properties of grafted polyrotaxanes as opposed to bottle brushes with static anchor points . The backbone stiffness is as well affected by the local anchor-point density, and a temporary rearrangement allows for a locally enhanced flexibility, even hairpin conformations …”

Section: Introductionmentioning

confidence: 99%

“…6 On the other hand, experiments have shown that hairpin conformations are possible as well in free polyrotaxane molecules, if their rotor density remains significantly below the saturation density. 7 Another degree of complexity is added to the polyrotaxane when polymers are densely grafted onto the rotors to create cylindrical polymer brushes with sliding anchors. 8,9 The osmotic pressure generated by the brush then leads to an exceptionally high stiffness of the complex, which allows the assembly of highly ordered films under flow.…”

Section: Introductionmentioning

confidence: 99%

“…Such a complex could therefore qualify as a drug-delivery system. 7,8 In the present work, we apply the scaling theory of polymer brushes, initially developed by Alexander 15 and deGennes, 16 to grafted polyrotaxane complexes. In many aspects, grafted rotaxanes behave similar to bottle brushes (which have their side chains grafted onto fixed anchors).…”

Section: Introductionmentioning

confidence: 99%

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Grafted Polyrotaxanes: Scaling Theory and Molecular Dynamics Simulations

Merlitz

Cui

et al. 2014

Macromolecules

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We analyze the scaling properties of grafted polyrotaxanes and compare the resulting scaling laws with molecular dynamics simulations. These molecules display a resemblance to bottle brushes, but the mobility of the rotors yields a backbone tension that is uniform along its contour. Properties like brush extension, backbone tension, and rotor mobility as functions of rotor density and degree of polymerization of grafted chains are well covered by a simple scaling model. The dynamics of rotor release after a breakup of the polyrotaxanea process recently observed in laboratory experi-mentsis studied in detail. It consists of three stages: a rapid backbone retraction, a driven rotor expulsion, and a diffusive transport. The complexity of this process, which may be exploited for drug delivery systems, is asking for further in-depth simulation studies.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Grafted Polyrotaxanes: Scaling Theory and Molecular Dynamics Simulations

Merlitz

Cui

et al. 2014

Macromolecules

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Tuning the Solution Self‐Assembly of a Peptide‐PEG (Polyethylene Glycol) Conjugate with α‐Cyclodextrin

Castelletto,

Kowalczyk,

Seitsonen

et al. 2023

ChemBioChem

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Cyclodextrins are saccharide ring molecules which act as host cavities that can encapsulate small guest molecules or thread polymer chains. We investigate the influence of alpha‐cyclodextrin (αCD) on the aqueous solution self‐assembly of a peptide‐polymer conjugate YYKLVFF‐PEG3K previously studied by our group [Castelletto et al., Polym. Chem., 2010, 1, 453–459]. This conjugate comprises a designed amyloid‐forming peptide YYKLVFF that contains the KLVFF sequence from Amyloid β peptide, Aβ16‐20, along with two aromatic tyrosine residues to enhance hydrophobicity as well as polyethylene glycol PEG with molar mass 3000 g mol‐1. The conjugate self‐assembles into β‐sheet fibrils in aqueous solution. Here we show that complexation with αCD leads instead can produce free‐floating nanosheets in aqueous solution (with a β‐sheet structure). The transition from fibrils to nanosheets is driven by an increase in the number of αCD molecules threaded on the PEG chains, as determined by 1H NMR spectroscopy. These findings point to the use of cyclodextrin additives as a powerful means to tune the solution self‐assembly in peptide‐polymer conjugates and potentially other polymer/biomolecular hybrids.

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Composite materials based on slide‐ring polyrotaxane structures for optoelectronics

Resmerita,

Asandulesa,

Farcas

2024

Journal of Polymer Science

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Composite material based on polyethylene glycol (PEG) and polypyrrole (PPy) polyrotaxanes both encapsulated into α‐cyclodextrins (α‐CDs) macrocycle molecules was synthesized by cross‐linking reaction. The effect of PPy‐αCD polyrotaxane incorporation into the PEG‐αCD polyrotaxane matrix, on the structural, morphological, thermal, and dielectric properties was evaluated and compared to the reference material. Scanning electron microscopy spectroscopy indicates different surface morphologies of this material in comparison to the reference one. In addition, the contact angle measurements and surface free energy attest a hydrophilic surface, while the reference material exhibits a hydrophobic surface. More than that, the presence of the PPy‐αCD cross‐linked into the matrix has a beneficial effect on the thermal properties. The composite material shows an enhanced dielectric constant value of 31,365 at 10 Hz frequency compared to the 38.2 of the reference material, and higher dielectric loss (62,398 vs. 80 at 10 Hz, respectively). The conductivity measurements at 10 Hz frequency indicated for the reference material the value 4.5 × 10−11, while for the material with PPy‐αCD polyrotaxane, the conductivity is three orders of magnitude higher (3.5 × 10−8) confirming the improvements of the electrical properties.

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New Insights on the Self‐Organization of PEG/α‐Cyclodextrin‐Based Polyrotaxanes in Solution: An Experimental and Theoretical Study

Cited by 4 publications

References 75 publications

Grafted Polyrotaxanes: Scaling Theory and Molecular Dynamics Simulations

Grafted Polyrotaxanes: Scaling Theory and Molecular Dynamics Simulations

Tuning the Solution Self‐Assembly of a Peptide‐PEG (Polyethylene Glycol) Conjugate with α‐Cyclodextrin

Composite materials based on slide‐ring polyrotaxane structures for optoelectronics

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