Dynamic self-consistent field theory for unentangled homopolymer fluids.

Area of Science:

• Polymer physics
• Soft matter physics
• Computational fluid dynamics

Background:

• Understanding polymer behavior at interfaces is crucial for material properties.
• Existing theories often struggle with complex dynamics and compressibility.
• Inhomogeneous polymer systems present significant modeling challenges.

Purpose of the Study:

• To present a novel lattice formulation of dynamic self-consistent field (DSCF) theory.
• To enable the resolution of interfacial structure, dynamics, and rheology in inhomogeneous polymer systems.
• To model compressible melts and blends of unentangled homopolymer chains.

Main Methods:

• Developed a lattice DSCF theory approximating segment distributions with one-body probabilities.
• Modeled flow effects on chain conformations using finitely extensible, nonlinearly elastic dumbbells (Peterlin approximation).
• Derived mean field transport equations for segment probabilities and momentum densities on the Kuhn length scale.

Main Results:

• The DSCF theory successfully models interfacial structure, dynamics, and rheology.
• It captures diffusive and viscous flux contributions arising from segmental hops.
• Applied to study transient and steady-state behavior in sheared planar channels with one- or two-component blends.

Conclusions:

• The lattice DSCF theory provides a robust framework for studying complex polymer systems.
• It offers insights into the interplay of structure, dynamics, and rheology at interfaces.
• This method is applicable to both one-component melts and phase-separated polymer blends.