Mixing protocols determine liquid-liquid phase separation dynamics in polyelectrolyte complex coacervation

Area of Science:

• Polymer Science
• Biophysics
• Soft Matter Physics

Background:

• Polyelectrolyte complex coacervation is crucial for biological processes.
• Understanding the influence of initial conditions on liquid-liquid phase separation (LLPS) is vital.

Purpose of the Study:

• To investigate how different initial mixing protocols affect polyelectrolyte complex coacervation dynamics.
• To elucidate the scaling laws governing coacervate domain growth under varied initial conditions.

Main Methods:

• Molecular dynamics simulations were employed.
• Simulations analyzed coacervate domain growth kinetics for different initial polymer arrangements.

Main Results:

• Randomly mixed polycations and polyanions showed initial t^1/2 scaling, followed by t¹ or t^1/3 scaling based on mixing degree.
• Spatially separated polycations and polyanions exhibited t^2/3 early-stage growth, mimicking marine organism LLPS.
• Preformed polyion pairs demonstrated classical t^1/3 coarsening dynamics.

Conclusions:

• Initial conditions profoundly influence polyelectrolyte complex coacervation LLPS dynamics.
• Distinct growth mechanisms and scaling laws emerge from different initial mixing strategies.
• Tailoring initial conditions can control LLPS kinetics in polyelectrolyte systems.