Connecting the Stimuli-Responsive Rheology of Biopolymer Hydrogels to Underlying Hydrogen-Bonding Interactions
Autor: | Federica Burla, Gijsje H. Koenderink, Giulia Giubertoni, Huib J. Bakker |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
chemistry.chemical_classification
Polymers and Plastics Hydrogen bond Organic Chemistry 02 engineering and technology Polymer engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Viscoelasticity Article 0104 chemical sciences Inorganic Chemistry Reptation chemistry Rheology Chemical engineering Self-healing hydrogels Materials Chemistry Stress relaxation engineering Biopolymer 0210 nano-technology |
Zdroj: | Macromolecules Macromolecules, 53(23) |
ISSN: | 1520-5835 0024-9297 |
Popis: | Many biopolymer hydrogels are environmentally responsive because they are held together by physical associations that depend on pH and temperature. Here we investigate how the pH and temperature response of the rheology of hyaluronan hydrogels is connected to the underlying molecular interactions. Hyaluronan is an essential structural biopolymer in the human body with many applications in biomedicine. Using two-dimensional infrared (2DIR) spectroscopy, we show that hyaluronan chains become connected by hydrogen bonds when the pH is changed from 7.0 to 2.5, and that the bond density at pH 2.5 is independent of temperature. Temperature-dependent rheology measurements show that due to this hydrogen bonding the stress relaxation at pH 2.5 is strongly slowed down in comparison to pH 7.0, consistent with the sticky reptation model of associative polymers. From the flow activation energy we conclude that each polymer is crosslinked by multiple (5-15) hydrogen bonds to others, causing slow macroscopic stress relaxation, despite the short time scale of breaking and reformation of each individual hydrogen bond. Our findings can aid the design of stimuli-responsive hydrogels with tailored viscoelastic properties for biomedical applications. |
Databáze: | OpenAIRE |
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