Dynamical self-consistent field theory captures multi-scale physics during spinodal decomposition in a symmetric...

Area of Science:

• Materials Science
• Polymer Physics
• Soft Matter Physics

Background:

• Spinodal decomposition is a critical process in polymer blends, influencing material properties.
• Understanding the dynamics of phase separation is essential for controlling blend morphology.
• Existing theoretical models often struggle to capture the full range of dynamics in polymer blends.

Purpose of the Study:

• To study spinodal decomposition in a symmetric, binary homopolymer blend.
• To validate a newly developed dynamical self-consistent field theory (DSCFT).
• To analyze both early-time instability and late-time coarsening dynamics.

Main Methods:

• Developed and applied a novel dynamical self-consistent field theory (DSCFT).
• Reduced multi-chain dynamics to a single-chain Smoluchowski equation within a mean-field.
• Numerically solved the Smoluchowski equation using large ensembles of Langevin dynamics simulations.

Main Results:

• Observed early-time spinodal instability within one Rouse time after quenching.
• Identified dominant unstable wavelengths on the order of the polymer coil size.
• Confirmed late-time domain growth follows the Lifshitz-Slyozov-Wagner t^1/3 power law.

Conclusions:

• The new DSCFT method accurately captures both early and late-time physics of spinodal decomposition.
• The simulation successfully modeled domain coarsening over five orders of magnitude in time.
• The results validate the DSCFT approach for studying polymer blend dynamics and phase separation.