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Updated: Aug 13, 2026
07:59
Molecular Entanglement and Electrospinnability of Biopolymers
Published on: September 3, 2014
Giant intrinsic viscosity coefficients of two-dimensional macromolecules
Senping Liu1, Yixuan Liang2, Yiwei Zhang1
1MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China. zhenxu@zju.edu.cn.
Soft Matter
|August 12, 2026
Summary
Flexible graphene oxide (GO) sheets exhibit a unique flat-scrolling transition in shear flow, leading to exceptionally high intrinsic viscosity coefficients (K) in suspensions. This discovery advances understanding of complex fluid dynamics and soft matter rheology.
Area of Science:
- Colloid and Interface Science
- Polymer Physics
- Rheology
Background:
- The intrinsic viscosity coefficient (K) quantifies particle influence on fluid viscosity, with Einstein's value of 2.5 for spheres serving as a baseline.
- Deviations from spherical shape and particle deformability significantly alter K values in colloidal dispersions.
- Soft two-dimensional macromolecules (2DMs) present complex rheological behaviors due to their deformability and potential topology transitions in flow fields.
Purpose of the Study:
- To investigate the rheological properties of dilute suspensions of graphene oxide (GO), a soft two-dimensional macromolecule.
- To understand the impact of GO's topology transitions on its intrinsic viscosity coefficient (K).
- To develop a new model predicting viscosity in soft 2DM suspensions considering topology deformation.
Main Methods:
- Experimental measurement of intrinsic viscosity coefficient (K) for dilute graphene oxide (GO) suspensions.
- Theoretical analysis of GO's behavior in shear fields, including topology transitions.
- Development and validation of a new viscosity model incorporating soft 2DM topology deformation.
Main Results:
- Observed exceptionally large K values, up to 3.01 × 10^7, for flexible GO suspensions, significantly exceeding theoretical predictions for rigid platelets.
- Demonstrated a reversible flat-to-scroll topology transition in GO under shear.
- Showed that this topology deformation dramatically increases GO's hydrodynamic volume, explaining the high K values.
Conclusions:
- Flexible 2DMs like GO exhibit significantly higher intrinsic viscosity due to topology deformation, challenging existing models.
- A novel viscosity model accounting for topology deformation accurately predicts the rheological behavior of GO suspensions.
- This research provides new insights into the rheology of complex suspensions and highlights the importance of particle-level topology changes.
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