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Connecting the Stimuli-Responsive Rheology of Biopolymer Hydrogels to Underlying Hydrogen-Bonding Interactions
- Source :
- Macromolecules, Macromolecules, 53(23)
- Publication Year :
- 2020
- Publisher :
- American Chemical Society, 2020.
-
Abstract
- 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.
- Subjects :
- 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
Subjects
Details
- Language :
- English
- ISSN :
- 15205835 and 00249297
- Volume :
- 53
- Issue :
- 23
- Database :
- OpenAIRE
- Journal :
- Macromolecules
- Accession number :
- edsair.doi.dedup.....72409fe2f4bac25aed48895a243366a4