Mesoscopic simulation on phase behavior of pluronic P123 aqueous solution

Area of Science:

• Polymer Science
• Computational Chemistry
• Materials Science

Background:

• Tri-block copolymers like P123 self-assemble into diverse structures in solution.
• Understanding these self-assembly processes is crucial for materials design and applications.
• Experimental studies provide phase diagrams but can be limited in scope.

Purpose of the Study:

• To simulate the microphase separation of P123 and water using a mesoscopic dynamic method.
• To investigate the formation of various aggregate structures (micelles, hexagonal, lamellar phases).
• To compare simulation results with experimental phase data and understand discrepancies.

Main Methods:

• Utilized the mesoscopic dynamics (MesoDyn) method, a dynamic density functional approach.
• Employed a simplified model for the tri-block copolymer P123 ((EO)20(PO)70(EO)20).
• Simulated the binary mixture of P123 and water under controlled conditions.

Main Results:

• Successfully reproduced micelle, hexagonal, and lamellar aggregate structures of P123 in water.
• Partially reproduced experimental phase regions, with deviations noted at high polymer concentrations.
• Observed good agreement with previous studies on micelle size trends in dilute solutions.
• Determined that the amount of poly(propylene oxide) (PO) influences morphology and formation rate.

Conclusions:

• Mesoscopic dynamics simulation is a valuable tool for studying copolymer aggregate formation.
• Simulation results complement experimental findings and provide insights into phase behavior.
• Discrepancies between simulation and experiment may arise from differences in applied forces (shear vs. external).