Strong-Segregation Theory of Bicontinuous Phases in Block Copolymers

TL;DR

This paper develops a method to compute phase diagrams for starblock copolymers in the strong-segregation regime, identifying the gyroid G phase as the most stable bicontinuous structure and exploring effects of conformational asymmetry.

Contribution

It introduces a general approach to calculate free energies in the strong-segregation limit for complex copolymer phases, including bicontinuous minimal surface structures.

Findings

Gyroid G phase is most nearly stable among bicontinuous phases.

Method effectively computes phase diagrams considering minimal surface structures.

Conformational asymmetry influences phase topology.

Abstract

We compute phase diagrams for $A_nB_m$ starblock copolymers in the strong-segregation regime as a function of volume fraction $\phi$, including bicontinuous phases related to minimal surfaces (G, D, and P surfaces) as candidate structures. We present the details of a general method to compute free energies in the strong segregation limit, and demonstrate that the gyroid G phase is the most nearly stable among the bicontinuous phases considered. We explore some effects of conformational asymmetry on the topology of the phase diagram.