Binary Blends of Diblock Copolymers: An Effective Route to Novel Bicontinuous Phases

TL;DR

This study uses polymeric self-consistent field theory to show that binary blends of diblock copolymers can stabilize novel bicontinuous phases, expanding the range of achievable nanostructures.

Contribution

It introduces a theoretical approach demonstrating how binary blends of diblock copolymers can stabilize metastable bicontinuous phases through designed dispersity.

Findings

Double-diamond and plumber's nightmare phases can be stabilized.

Segregation at nodes relieves packing frustration.

Local segregation influences interfacial curvature.

Abstract

The formation of various bicontinuous phases from binary blends of linear AB diblock copolymers (DBCPs) is studied using the polymeric self-consistent field theory. The theoretical study predicts that the double-diamond and the "plumber's nightmare" phases, which are metastable for neat diblock copolymers, could be stabilized in block copolymers with designed dispersity, namely, binary blends composed of a gyroid-forming DBCP and a homopolymer-like DBCP. The spatial distribution of different monomers reveals that these two types of DBCPs are segregated such that the homopolymer-like component is localized at the nodes to relieve the packing frustration. Simultaneously, the presence of a local segregation of the two DBCPs on the AB interface regulates the interfacial curvature. These two mechanisms could act in tandem for homopolymer-like diblock copolymers with proper compositions, resulting in larger stability regions for the novel bicontinuous phases.