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Updated: Aug 17, 2026

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Published on: June 7, 2018
Does coarsening begin during the initial stages of spinodal decomposition?
Timothy J Rappl1, Nitash P Balsara
1Department of Chemical Engineering, University of California, Berkeley, California 94720, USA.
Spinodal decomposition in polyolefins begins immediately after a pressure quench. This study challenges the Cahn-Hilliard-Cook theory by showing early coarsening during phase separation.
Area of Science:
- Polymer Science
- Materials Science
- Physical Chemistry
Background:
- Spinodal decomposition is a critical process in polymer blends.
- The Cahn-Hilliard-Cook theory is the established model for spinodal decomposition.
- Understanding early-stage phase separation is crucial for material properties.
Purpose of the Study:
- To investigate the initial stages of spinodal decomposition in critical polyolefin blends.
- To challenge or validate the Cahn-Hilliard-Cook theory under specific experimental conditions.
- To observe the onset and progression of phase separation immediately following a perturbation.
Main Methods:
- Utilizing a critical blend of model polyolefins.
- Applying a rapid pressure quench to induce phase separation.
- Employing time-resolved small-angle neutron scattering (TR-SAXS) to monitor structural evolution.
Main Results:
- Phase-separated structures begin coarsening immediately after the pressure quench.
- Coarsening occurs throughout the entire initial stage of spinodal decomposition.
- Experimental observations contradict the predictions of the Cahn-Hilliard-Cook theory regarding the initiation of coarsening.
Conclusions:
- The Cahn-Hilliard-Cook theory may not fully capture the dynamics of early-stage spinodal decomposition in all polymer systems.
- Immediate coarsening is a key feature of spinodal decomposition in these polyolefin blends.
- Further theoretical and experimental work is needed to refine models of phase separation kinetics.
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