Self-assembly in rod/coil block copolymers: Degenerate behavior under nonconfinement

TL;DR

This study investigates the complex self-assembly behaviors of rod/coil ABC triblock copolymers, revealing degenerate phases and the importance of chain entropy, providing theoretical insights into their rich phase behavior.

Contribution

It introduces a theoretical model showing degenerate morphologies in rod/coil triblock copolymers under asymmetric interactions, highlighting the role of chain entropy.

Findings

Identification of multiple stable phases including lamellae, gyroids, and wavy morphologies.

Discovery of degenerate structures such as NCSLM and CSLM.

Demonstration of the significance of chain conformation entropy in phase behavior.

Abstract

The self-assembly of block copolymers containing rigid blocks have received abiding attention due to its rich phase behavior and potential for use in a variety of applications. In this work, under asymmetric interactions between rod/coil components, the self-assembly of coil/coil/rod ABC triblock copolymers is studied using self-consistent field of lattice model. In addition to micelles, centrosymmetric lamellae (CSLM), lamellae, perforated lamellae, strips and gyroids, non-centrosymmetric (NCSLM) lamellae and wavy morphologies are observed as stable phases. The phase diagram of interaction between rod and coil components versus the rod fraction is constructed given a fixed interaction between coil components. For intermediate rod fraction, degenerate behavior is observed. NCSLM and CSLM are degenerate structures. It is found that the entropy of chain conformation plays an important role for this rich behavior. A mechanism of the degenerate behavior is proposed in coil/rod block copolymers under noncofinement. This study provides some new insights into the degenerate behavior of block compolymers, which can offer a theoretical reference for related experiments.