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Decoupling between Translational Diffusion and Viscoelasticity in Transient Networks with Controlled Network
Takuya Katashima1, Ryunosuke Kobayashi1, Shohei Ishikawa1
1Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Gels (Basel, Switzerland)
|December 22, 2022
Summary
Transient polymer networks exhibit unique viscoelastic and diffusion properties. Their relaxation is not solely driven by polymer diffusion, especially at low connectivity, challenging conventional understanding.
Area of Science:
- Polymer Physics
- Materials Science
- Rheology
Background:
- Molecular mobility in polymeric liquids is governed by viscoelasticity, closely linked to diffusion.
- Previous studies on transient networks, crucial viscoelastic liquids, were limited by the lack of suitable model systems.
- Understanding these networks is vital for applications involving dynamic polymer materials.
Purpose of the Study:
- To investigate and compare the viscoelastic and diffusional properties of transient polymer networks.
- To explore the relationship between network connectivity and these properties using a model system.
- To challenge conventional models of viscoelastic relaxation in such systems.
Main Methods:
- Utilized a model system, Tetra-PEG slime, with controlled network connectivity.
- Performed independent measurements of viscoelastic properties and diffusion coefficients.
- Analyzed the root-mean-square distance polymers diffuse during viscoelastic relaxation time.
Main Results:
- Observed a significant deviation between polymer diffusion distance and polymer self-size during relaxation time.
- This decoupling is contrary to the established understanding of polymer dynamics in viscoelastic liquids.
- The effect is particularly pronounced in networks with low connectivity.
Conclusions:
- Transient networks exhibit unique viscoelastic and diffusion behaviors distinct from conventional polymer liquids.
- Viscoelastic relaxation in these networks is not solely attributed to individual polymer diffusion, especially at low connectivity.
- Findings provide a foundation for a more accurate understanding of viscoelasticity in dynamic polymer networks.
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