Modeling solvent evaporation during thin film formation in phase separating polymer mixtures

Area of Science:

• Polymer Science
• Materials Science
• Chemical Engineering

Background:

• Thin film preparation via solvent evaporation is common but difficult to model.
• Existing models struggle with multi-scale phenomena in evaporating solvent systems.

Purpose of the Study:

• To develop a robust methodology for modeling thin film formation from polymer solutions.
• To investigate the influence of solvent evaporation and polymer thermodynamics on thin film microstructures.

Main Methods:

• Utilized linear non-equilibrium thermodynamics to model solvent evaporation and polymer behavior.
• Derived evaporative flux and boundary conditions for near-equilibrium simulations.
• Applied the methodology to phase-segregating polymer blends on a substrate.

Main Results:

• The methodology systematically accounts for solvent phase transformation and polymer thermodynamics.
• Enabled study of evaporation rates, substrate interactions, and concentration-dependent mobilities.
• Investigated the microstructural evolution of thin polymer blend films.

Conclusions:

• The developed thermodynamic approach provides a framework for understanding thin film formation.
• Offers insights into controlling thin film microstructure through process parameters.
• Facilitates more accurate simulations of polymer thin film fabrication.