Kinetics of phase separation in polymer-solvent mixtures

Area of Science:

• Physical Chemistry
• Materials Science
• Polymer Science

Background:

• Phase separation is crucial in polymer-solvent mixtures, leading to distinct phases.
• The polymer-rich phase often forms a gel with significantly reduced mobility.
• Understanding segregation kinetics is key to controlling material properties.

Purpose of the Study:

• To investigate the kinetics of phase separation in systems with high mobility asymmetry.
• To model the segregation behavior of polymer-solvent mixtures.
• To analyze the impact of thermal noise on domain growth dynamics.

Main Methods:

• Detailed numerical simulations were performed.
• The model system incorporates strong asymmetry in phase mobility.
• Simulations were conducted both with and without thermal noise.

Main Results:

• In the absence of thermal noise, domain growth significantly slows when the low-mobility phase percolates.
• Thermal noise was found to restore rapid domain growth.
• A Brownian coalescence mechanism was identified as responsible for accelerated growth.

Conclusions:

• Mobility asymmetry profoundly impacts phase separation kinetics.
• Percolation of low-mobility phases acts as a significant bottleneck for domain growth.
• Thermal fluctuations are essential for overcoming kinetic arrest and enabling rapid domain coarsening.