Phase Separation Dynamics of Polymer Systems

To understand viscoelastic phase separation dynamics occurring in polymer systems, we propose a modified two-fluid model from nonequilibrium thermodynamics which obeys an energy dissipation relation. Numerical results demonstrate that our model can reproduce the expected physical phenomena such has volume shrinking and phase inversion and also maintain better stability properties. Our further investigations suggest that these important phenomena are most likely caused by a diffusion asymmetry of constituent molecules in the system.

We propose a time-dependent Ginburg-Landau model to understand the coupled dynamical phenomena between phase separation and crystallization observed in experiments conducted by the Institute of Chemistry at Chinese Academy of Sciences. Our modeling and simulation corroborate a recently proposed mechanism of “phase separation fluctuation assisted nucleation” during the crystallization process.