Fundamentals of Phase Separation in Polymer Blend Thin Films

1. Front Matter

   Pages i-xvi

   PDF

2. Introduction

   • Sam Coveney

   Pages 1-6

3. Development of Theory for Bulk Polymer Blend Systems

   • Sam Coveney

   Pages 7-34

4. Development of Theory for Polymer-Blend Thin Films

   • Sam Coveney

   Pages 35-53

5. Hamiltonian Phase Portraits for Polymer-Blend Thin Films

   • Sam Coveney

   Pages 55-82

6. Lateral Phase Separation via Surface Bifurcation

   • Sam Coveney

   Pages 83-119

7. A 3D Model of Phase Separation Coupled to Surface Roughening

   • Sam Coveney

   Pages 121-140

8. Summary of Research and Outlook

   • Sam Coveney

   Pages 141-144

9. Back Matter

   Pages 145-171

   PDF

This work sheds new light on fundamental aspects of phase separation in polymer-blend thin films. A key feature underlying the theoretical models is the unification of one-dimensional thermodynamic phase equilibria with film evolution phenomena in two- and three dimensions. Initially, an established 'phase portrait' method, useful for visualising and calculating phase equilibria of polymer-blend films, is generalised to systems without convenient simplifying symmetries. Thermodynamic equilibria alone are then used to explain a film roughening mechanism in which laterally coexisting phases can have different depths in order to minimise free energy. The phase portraits are then utilised to demonstrate that simulations of lateral phase separation via a transient wetting layer, which conform very well with experiments, can be satisfactorily explained by 1D phase equilibria and a 'surface bifurcation' mechanism. Lastly, a novel 3D model of coupled phase separation and dewetting is developed, which demonstrates that surface roughening shadows phase separation in thin films.

• 3D Dewetting Model
• Dewetting Coupled to Phase Separation
• Diffusion Simulations of Polymer Films
• Hamiltonian Phase Portraits
• Phase Equilibria of Polymer Films
• Phase Portraits of Polymer Films
• Phase Separation in Polymer-blend Thin Films
• Roughening of Polymer-blend Thin Films
• Thermodynamics of Polymer Films
• Thin Film Morphology

• Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom

  Sam Coveney

This work sheds new light on fundamental aspects of phase separation in polymer-blend thin films. A key feature underlying the theoretical models is the unification of one-dimensional thermodynamic phase equilibria with film evolution phenomena in two- and three dimensions. Initially, an established 'phase portrait' method, useful for visualising and calculating phase equilibria of polymer-blend films, is generalised to systems without convenient simplifying symmetries. Thermodynamic equilibria alone are then used to explain a film roughening mechanism in which laterally coexisting phases can have different depths in order to minimise free energy. The phase portraits are then utilised to demonstrate that simulations of lateral phase separation via a transient wetting layer, which conform very well with experiments, can be satisfactorily explained by 1D phase equilibria and a 'surface bifurcation' mechanism. Lastly, a novel 3D model of coupled phase separation and dewetting is developed, which demonstrates that surface roughening shadows phase separation in thin films.

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