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Updated: Jun 17, 2026

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

Viscous solvent embrittles long-chain polymer networks.

Haeji Kim¹, Diogo Costa¹, Junsoo Kim¹

¹Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, 60208, USA. junsoo.kim@northwestern.edu.

|June 16, 2026

Summary

Toughness in polymer networks can decrease with higher solvent viscosity for long polymer chains. This occurs because increased viscosity limits tension transmission along chains at crack tips, reducing overall toughness.

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Area of Science:

Materials Science
Polymer Physics
Rheology

Background:

Polymer network toughness is often linked to viscoelastic energy dissipation.
A common design principle suggests higher viscosity enhances toughness.

Purpose of the Study:

To investigate the relationship between solvent viscosity and polymer network toughness.
To explore how polymer chain length influences this relationship.

Main Methods:

Preparation of polyacrylamide hydrogels with identical network structures.
Controlled variation of solvent viscosity using glycerol-water mixtures.
Mechanical testing including pure shear and trouser tests.

Main Results:

Toughness significantly decreases with increasing solvent viscosity for long polymer chains.
A master curve for toughness was observed, dependent on the product of viscosity and velocity.
Embrittlement is attributed to limited tension transmission along polymer chains at the crack tip.

Conclusions:

The inverse relationship between viscosity and toughness in long-chain polymer networks challenges conventional design principles.
Understanding tension transmission and viscous dissipation is crucial for predicting polymer network toughness.
This study provides new insights into the dynamics of fracture in viscoelastic materials.