Mechanisms and kinetics of the crystal thickening of poly(butadiene)-block-poly(ethylene oxide) during annealing within the melting range

Hölzer, Stefan M.; Büttner, Tobias N.; Schulze, Robert; Arras, Matthias M. L.; Schacher, Felix H.; Schubert, Ulrich S.

doi:10.1016/j.eurpolymj.2015.04.010

Cited by 8 publications

(3 citation statements)

References 44 publications

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“…This observation explains the broad melting peak in the DSC, which correlates with a broad distribution of different crystal species. 30,31 Likewise, the uniform long and parallel aligned crystals of the block copolymer P9 and the PεCL homopolymer P10 are in agreement with the narrower DSC peak. The comparison of the lamella widths with the calculated polymer chain length (Table 2) revealed that the crystal domains are created by chain folds, which is typical for polymers.…”

Section: ■ Results and Discussionsupporting

confidence: 69%

Maintaining the Hydrophilic–Hydrophobic Balance of Polyesters with Adjustable Crystallinity for Tailor-Made Nanoparticles

et al. 2018

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To explore the relationship between thermal properties of a polymer and the biological performance of the resulting nanoparticle, all other parameters, including the hydrophobicity, should be kept constant. For this purpose, a gradient and a block copolyester were tailor-made via the triazabicyclodecene catalyzed ring-opening copolymerization of δ-valerolactone (δVL) and δ-decalactone (δDL) to match the hydrophobicity of poly(ε-caprolactone) (PεCL). The degree of crystallinity of the semicrystalline materials was significantly reduced due to the incorporation of amorphous PδDL segments, as confirmed by dynamic scanning calorimetry. Atomic force microscopy revealed short and randomly oriented crystals in the gradient copolymer but longer and parallel aligned crystals for the block copolymer and PεCL. The stiffness of nanoparticles (D h ≈ 170 nm) prepared from the polyesters correlated to the bulk crystallinity. The set of nanoparticles with constant hydrophobicity and size will facilitate direct access to the influence of the nanoparticle crystallinity on biological processes such as enzymatic degradation, drug release, and cellular uptake.

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Section: ■ Results and Discussionsupporting

confidence: 69%

Maintaining the Hydrophilic–Hydrophobic Balance of Polyesters with Adjustable Crystallinity for Tailor-Made Nanoparticles

et al. 2018

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“…This is to be expected based on the fact that crystal lamellar spacing is dictated by the critical nucleus size 69 . The shoulder that is only present in dry PEO, has a spacing of 22 nm, which has been observed in poly(butadiene)-PEO and PS-PEO BCPs crystalized at room temperature 66,70 . It is roughly twice the major crystal peak and might be caused by the mutual rearrangement of adjacent crystals 71 .…”

Section: Polymer Structurementioning

confidence: 70%

Crystallite dissolution in PEO-based polymers induced by water sorption

Oparaji

Zuo

Hallinan

2016

Polymer

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Poly(styrene-block-ethylene oxide) (PS-b-PEO) is a model hierarchically nanostructured polymer that contains PEO crystallites within microphase segregated block copolymer morphology. In order to investigate dynamics in this hierarchically nanostructured polymer, water was used as a selective, interacting probe molecule. First, the equilibrium effect of water sorption on the polymer structure was examined. Then, the coupled dynamics of structural changes and water diffusion were studied. At moderate water activity, crystallite dissolution caused water diffusion to appear non-Fickian (determined by Fourier Transform infraredattenuated total reflectance spectroscopy). PEO deliquescence was so extreme at high water activity that dynamics could not be measured in a homopolymer control. In the block copolymer at unity water activity, a second stage of water sorption occurred that was attributed to relaxation of the glassy PS phase. Water desorption was ten times faster than sorption. Desorption is thought to be less hindered by tortuosity resulting from PEO crystallites. These results are of interest for a wide-range of applications including batteries and fuel cells, water desalination, food packaging, and biomedical implants.

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“…Low molecular weight PEO polymer dissolves in the PMMA microdomains and morphological transitions are induced on increasing the PEO volume fraction, whereas high molecular weight PEO induces phase separation. The mechanism of crystal thickening and kinetics during annealing is usually studied by a combination of DSC and temperature‐ and time‐dependent X‐ray scattering . Hot stage AFM also enables the process to be followed in situ as evidenced by Frank and coworkers .…”

Section: Introductionmentioning

confidence: 99%

Investigation of the thin film crystallization of a DNA copolymer hybrid composed of chitosan

Safir

Chami

Buergi

et al. 2016

Polymer International

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We describe for the first time the crystallization in thin films of a DNA copolymer composed of a low molecular weight chitosan backbone to which a sequence of nucleic acids is grafted (chitosan‐g‐ssDNA). As assessed by atomic force microscopy, optical microscopy and spectroscopy, crystallization occurs due to intermolecular hydrogen bonding in which the nucleic acid strands engage. The morphology of the crystals depends on the affinity for the surface of the polymer segments that compose the DNA copolymer hybrid. The nucleic acids adsorb on mica and silica on which side‐branched structures are observed whereas chitosan interacts preferentially with gold, and dendritic crystals are assembled. Attenuated total reflectance infrared spectroscopy supports the high ordering of the structure and the establishment of strong intermolecular interactions by hydrogen bonding. © 2016 Society of Chemical Industry

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Mechanisms and kinetics of the crystal thickening of poly(butadiene)-block-poly(ethylene oxide) during annealing within the melting range

Cited by 8 publications

References 44 publications

Maintaining the Hydrophilic–Hydrophobic Balance of Polyesters with Adjustable Crystallinity for Tailor-Made Nanoparticles

Maintaining the Hydrophilic–Hydrophobic Balance of Polyesters with Adjustable Crystallinity for Tailor-Made Nanoparticles

Crystallite dissolution in PEO-based polymers induced by water sorption

Investigation of the thin film crystallization of a DNA copolymer hybrid composed of chitosan

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