Discontinuous Bubble Nucleation Due to a Metastable Condensation Transition in Polymer-CO2 Mixtures.
We combine a newly developed density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in compressible polymer-CO2 mixtures. Nucleation is initiated by saturating the polymer liquid with high pressure CO2 and subsequently reducing the pressure to ambient condition. Below a critical temperature, we find that there is a discontinuous drop in the nucleation barrier with increased initial CO2 pressure, as a result of an underlying metastable transition from a CO2-rich-vapor phase to a CO2-rich-liquid phase. This phenomenon is different from previously proposed nucleation mechanisms involving metastable transitions.
†Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Xiaofei
X
Xu
‡The Dow Chemical Company, Midland, Michigan 48674, United States.
Diego E
DE
Cristancho
‡The Dow Chemical Company, Midland, Michigan 48674, United States.
Stéphane
S
Costeux
†Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Zhen-Gang
ZG
Wang
discontinuous nucleation; metastable phase transition; minimum free energy path; string method