Mixing Linear Polymers with Rings and Catenanes: Bulk and Interfacial Behavior

Area of Science:

• Polymer Physics
• Soft Matter Science
• Computational Chemistry

Background:

• Understanding polymer mixtures is crucial for materials science.
• Ring polymers exhibit unique topological properties compared to linear chains.
• Phase separation behavior in complex polymer systems remains an active research area.

Purpose of the Study:

• To derive and parameterize effective interaction potentials for ring-linear polymer mixtures.
• To investigate phase behavior, including coexistence binodals and interfacial properties.
• To explore the influence of solvent quality and bending rigidity on mixture properties.

Main Methods:

• Derivation and parameterization of effective interaction potentials.
• Application of a density functional treatment for polymer mixtures.
• Analysis of coexistence binodals, response functions, and wetting behavior.

Main Results:

• Effective interaction potentials were developed for various ring-linear polymer combinations.
• Worsening solvent quality for rings enhances macroscopic phase separation in polycatenane mixtures.
• Phase separation is predominantly of the demixing type between phases of similar particle density.

Conclusions:

• A simple criterion based on effective interactions predicts demixing phase separation in linear-ring mixtures.
• Solvent quality is a key factor driving macroscopic phase separation in these complex polymer systems.
• The findings provide insights into designing polymer mixtures with controlled phase behavior.