Keywords
Phase transitions, Thermodynamic functions, Porous media, Mathematical modeling, Mass transfer, Diffusion, Degree of polymerization, Polymers, Field theory models
Abstract
Nonsolvent-induced phase separation (NIPS) is a popular method for creating polymeric particles with internal microstructure, but many fundamental questions remain surrounding the kinetics of the complex coupled mass transfer and phase separation processes. In this work, we use simulations of a phase-field model to examine how (i) finite domain boundaries of a polymer droplet and (ii) solvent/nonsolvent miscibility affect the NIPS process. To isolate the effects of phase separation kinetics and solvent/nonsolvent mass transfer on the NIPS process, we study two different cases. First, we investigate droplet concentrations that originate inside the two-phase region, where phase separation kinetics alone governs the microstructure. Second, we investigate the effects of solvent/nonsolvent mass transfer by studying droplet concentrations that begin outside the two-phase region, where both phase separation kinetics and mass transfer play a role. In both cases, we find that qualitative NIPS behavior is a strong function of the relative location of the initial droplet composition with respect to the phase diagram. We also find that polymer/nonsolvent miscibility competes with solvent/nonsolvent miscibility in driving NIPS kinetic behavior. Finally, we examine polymer droplets undergoing solvent/nonsolvent exchange and find that the model predicts droplets that shrink with nearly Fickian diffusion kinetics. We conclude with a brief perspective on the state of simulations of NIPS processes and some recommendations for future work.
Original Publication Citation
J. Chem. Phys. 158, 214903 (2023); https://doi.org/10.1063/5.0143928
BYU ScholarsArchive Citation
Alhasan, Rami; Wilcoxson, Tanner A.; Banks, Dakota S.; Jung, Sion; and Tree, Douglas R., "Nonsolvent-induced phase separation inside liquid droplets" (2023). Faculty Publications. 7132.
https://scholarsarchive.byu.edu/facpub/7132
Document Type
Peer-Reviewed Article
Publication Date
2023-06-01
Publisher
AIP Publishing
Language
English
College
Ira A. Fulton College of Engineering
Department
Chemical Engineering
Copyright Status
© 2023 AIP Publishing.
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