Dynamics of Isolated Polycaprolactone Chains in Their Inclusion Complexes with Cyclodextrins

Lu, Jin; Mirau, Peter A.; Tonelli, Alan E.

doi:10.1021/ma001820z

Cited by 83 publications

(96 citation statements)

References 36 publications

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“…As can be seen in Table 4, these expectations are in fact realized as indicated by the increased, decreased level of PCL block crystallinity in PCL-PPG-PCL coalesced from its α-,γ-CD-ICs. Because two side-by-side PCL blocks may be included in the channels of the γ-CD-IC [107,108], while only single PPG blocks may be included, the less than expected minor reduction in the phase segregation achieved upon coalescence from the PCL-PPG-PCL-γ-CD-IC can be understood. It should also be mentioned that block copolymers, such as PCL-PPG-PCL, may be utilized to form polymer-CD-ICs [102][103][104] that are effective as nucleating agents.…”

Section: Pcl-ppg-pcl [25]mentioning

confidence: 99%

Molecular Processing of Polymers with Cyclodextrins

Tonelli

2009

Advances in Polymer Science

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We summarize our recent studies employing the cyclic starch derivatives called cyclodextrins (CDs) to both nanostructure and functionalize polymers. Two important structural characteristics of CDs are taken advantage of to achieve these goals. First the ability of CDs to form noncovalent inclusion complexes (ICs) with a variety of guest molecules, including many polymers, by threading and inclusion into their relatively hydrophobic interior cavities, which are roughly cylindrical with diameters of ∼0.5 − 1.0 nm. α-, β-, and γ-CD contain six, seven, and eight α-1,4-linked glucose units, respectively. Warm water washing of polymer-CD-ICs containing polymer guests insoluble in water or treatment with amylase enzymes serves to remove the host CDs and results in the coalescence of the guest polymers into solid samples. When guest polymers are coalesced from the CD-ICs by removing their host CDs, they are observed to solidify with structures, morphologies, and even conformations that are distinct from bulk samples made from their solutions and melts. Molecularly mixed, intimate blends of two or more polymers that are normally immiscible can be obtained from their common CD-ICs, and the phase segregation of incompatible blocks can be controlled (suppressed or increased) in CD-IC coalesced block copolymers. In addition, additives may be more effectively delivered to polymers in the form of their crystalline CD-ICs or soluble CD-rotaxanes. Secondly, the many hydroxyl groups attached to the exterior rims of CDs, in addition to conferring water solubility, provide an opportunity to covalently bond them to polymers either during their syntheses or via postpolymerization reactions. Polymers containing CDs in their backbones or attached to their side chains are observed to more readily accept and retain additives, such as dyes and fragrances. Processing with CDs can serve to both nanostructure and functionalize polymers, leading to greater understanding of their behaviors and to new properties and applications.

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Section: Pcl-ppg-pcl [25]mentioning

confidence: 99%

Molecular Processing of Polymers with Cyclodextrins

Tonelli

2009

Advances in Polymer Science

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“…[12][13][14][15] These crystal domains make the pPRs insoluble in most common solvents. [16][17][18] Additionally, the few known solvents able to solubilize pPRs, such as dimethyl sulfoxide (DMSO) or ionic solvents, [ 19 ] generally also destabilize the supramolecular assembly due to cyclodextrin dethreading.…”

Section: Introductionmentioning

confidence: 99%

Star-Pseudopolyrotaxane Organized in Nanoplatelets for Poly(ε-caprolactone)-Based Nanofibrous Scaffolds with Enhanced Surface Reactivity

Oster

Hébraud

Gallet

et al. 2014

Macromol. Rapid Commun.

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Herein, it is demonstrated that star pseudopolyrotaxanes (star-pPRs) obtained from the inclusion complexation of α-cyclodextrin (CD) and four-branched star poly(ε-caprolactone) (star-PCL) organize into nanoplatelets in dimethyl sulfoxide at 35 °C. This peculiar property, not observed for linear pseudopolyrotaxanes, allows the processing of star-pPRs while preserving their supramolecular assembly. Thus, original PCL:star-pPR core:shell nanofibers are elaborated by coaxial electrospinning. The star-pPR shell ensures the presence of available CD hydroxyl functions on the fiber surface allowing its postfunctionalization. As proof of concept, fluorescein isothiocyanate is grafted. Moreover, the morphology of the fibers is maintained due to the star-pPR shell that acts as a shield, preventing the fiber dissolution during chemical modification. The proposed strategy is simple and avoids the synthesis of polyrotaxanes, i.e., pPR end-capping to prevent the CD dethreading. As PCL is widely used for biomedical applications, this strategy paves the way for simple functionalization with any bioactive molecules.

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“…[1] Another interesting aspect is the possibility to study local dynamics of the isolated polymer chain without the complications arising from cooperative motions, [1,2] which would usually dominate the relaxation properties of the chains in bulk. [3] As the picture of the dynamic behavior of polymers in inclusion compounds has not been clarified yet satisfactorily, [2,4,5] and NMR investigations of guest dynamics in inclusion compounds are generally rare, [2, 4 -7] we present the first quantitative solid-state NMR investigations of local segmental fluctuations and order in such a system. Our methods of choice are novel multiple-quantum magic-angle spinning (MAS) techniques, [8,9] which do not require isotopic labeling, and are well-suited to study local polymer dynamics very selectively.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of Poly(dimethylsiloxane) Chain Dynamics and Order in Its Inclusion Compound withγ-Cyclodextrin by Fast-MAS Solid-State NMR Spectroscopy

Saalwächter¹

2002

Macromol. Rapid Commun.

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The dynamics of poly(dimethylsiloxane) in its inclusion compound with γ‐cyclodextrin are elucidated using modern fast‐MAS solid‐state NMR techniques. Measurements of methyl 1H–1H and 1H–13C dipolar coupling constants indicate that the polymer undergoes a uniform motion, rendering all methyl groups equivalent. The dynamics of the Si—C bond is characterized by either a dynamic order parameter of S = 0.72, or, assuming a stably rotating helical structure, an inclination angle of 73° relative to the rotation axis.

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Dynamics of Isolated Polycaprolactone Chains in Their Inclusion Complexes with Cyclodextrins

Cited by 83 publications

References 36 publications

Molecular Processing of Polymers with Cyclodextrins

Molecular Processing of Polymers with Cyclodextrins

Star-Pseudopolyrotaxane Organized in Nanoplatelets for Poly(ε-caprolactone)-Based Nanofibrous Scaffolds with Enhanced Surface Reactivity

An Investigation of Poly(dimethylsiloxane) Chain Dynamics and Order in Its Inclusion Compound withγ-Cyclodextrin by Fast-MAS Solid-State NMR Spectroscopy

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