This title appears in the Scientific Report :
2021
Please use the identifier:
http://hdl.handle.net/2128/28361 in citations.
Please use the identifier: http://dx.doi.org/10.3390/polym13142235 in citations.
Chain-End Effects on Supramolecular Poly(ethylene glycol) Polymers
Chain-End Effects on Supramolecular Poly(ethylene glycol) Polymers
In this work we present a fundamental analysis based on small-angle scattering, linear rheology and differential scanning calorimetry (DSC) experiments of the role of different hydrogen bonding (H-bonding) types on the structure and dynamics of chain-end modified poly(ethylene glycol) (PEG) in bulk....
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Personal Name(s): | Bras, Ana (Corresponding author) |
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Arizaga, Ana / Agirre, Uxue / Dorau, Marie / Houston, Judith / Radulescu, Aurel / Kruteva, Margarita / Pyckhout-Hintzen, Wim / Schmidt, Annette M. | |
Contributing Institute: |
JCNS-4; JCNS-4 Neutronenstreuung; JCNS-1 Heinz Maier-Leibnitz Zentrum; MLZ JCNS-FRM-II; JCNS-FRM-II |
Published in: | Polymers, 13 (2021) 14, S. 2235 |
Imprint: |
Basel
MDPI
2021
|
DOI: |
10.3390/polym13142235 |
Document Type: |
Journal Article |
Research Program: |
Materials – Quantum, Complex and Functional Materials Jülich Centre for Neutron Research (JCNS) (FZJ) |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.3390/polym13142235 in citations.
In this work we present a fundamental analysis based on small-angle scattering, linear rheology and differential scanning calorimetry (DSC) experiments of the role of different hydrogen bonding (H-bonding) types on the structure and dynamics of chain-end modified poly(ethylene glycol) (PEG) in bulk. As such bifunctional PEG with a molar mass below the entanglement mass Me is symmetrically end-functionalized with three different hydrogen bonding (H-bonding) groups: thymine-1-acetic acid (thy), diamino-triazine (dat) and 2-ureido-4[1H]-pyrimidinone (upy). A linear block copolymer structure and a Newtonian-like dynamics is observed for PEG-thy/dat while results for PEG-upy structure and dynamics reveal a sphere and a network-like behavior, respectively. These observations are concomitant with an increase of the Flory–Huggins interaction parameter from PEG-thy/dat to PEG-upy that is used to quantify the difference between the H-bonding types. The upy association into spherical clusters is established by the Percus–Yevick approximation that models the inter-particle structure factor for PEG-upy. Moreover, the viscosity study reveals for PEG-upy a shear thickening behavior interpreted in terms of the free path model and related to the time for PEG-upy to dissociate from the upy clusters, seen as virtual crosslinks of the formed network. Moreover, a second relaxation time of different nature is also obtained from the complex shear modulus measurements of PEG-upy by the inverse of the angular frequency where G’ and G’’ crosses from the network-like to glass-like transition relaxation time, which is related to the segmental friction of PEG-upy polymeric network strands. In fact, not only do PEG-thy/dat and PEG-upy have different viscoelastic properties, but the relaxation times found for PEG-upy are much slower than the ones for PEG-thy/dat. However, the activation energy related to the association dynamics is very similar for both PEG-thy/dat and PEG-upy. Concerning the segmental dynamics, the glass transition temperature obtained from both rheological and calorimetric analysis is similar and increases for PEG-upy while for PEG-thy/dat is almost independent of association behavior. Our results show how supramolecular PEG properties vary by modifying the H-bonding association type and changing the molecular Flory–Huggins interaction parameter, which can be further explored for possible applications |