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Updated: Jul 28, 2025

Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure
Published on: April 17, 2018
Nonsolvent-induced phase separation inside liquid droplets
Rami Alhasan1, Tanner A Wilcoxson2, Dakota S Banks1
1Chemical Engineering Department, Brigham Young University, Provo, Utah 84602, USA.
Simulations reveal how polymer droplet boundaries and solvent miscibility influence nonsolvent-induced phase separation (NIPS) kinetics. Initial composition relative to the phase diagram dictates microstructure formation during NIPS.
Area of Science:
- Polymer Science
- Materials Science
- Chemical Engineering
Background:
- Nonsolvent-induced phase separation (NIPS) is crucial for creating polymeric microstructures.
- Fundamental understanding of NIPS kinetics, including mass transfer and phase separation, is lacking.
Purpose of the Study:
- To investigate the impact of finite domain boundaries and solvent/nonsolvent miscibility on NIPS kinetics using simulations.
- To differentiate the roles of phase separation kinetics versus mass transfer in NIPS.
Main Methods:
- Phase-field modeling simulations were employed.
- Two cases were studied: initial compositions within and outside the two-phase region of the phase diagram.
- Analysis focused on droplet concentrations and solvent/nonsolvent exchange.
Main Results:
- NIPS behavior is highly dependent on the initial droplet composition's location relative to the phase diagram.
- Polymer/nonsolvent miscibility competes with solvent/nonsolvent miscibility in influencing NIPS kinetics.
- Simulations predict droplet shrinkage with near-Fickian diffusion kinetics during solvent/nonsolvent exchange.
Conclusions:
- The study provides insights into the complex interplay of factors governing NIPS.
- Recommendations for future simulation-based research in NIPS processes are offered.
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