Self-assembly behaviour of diblock copolymer-diblock copolymer under oscillating shear field

TL;DR

This study uses cell dynamics simulation to explore how oscillating shear fields influence the self-assembly and phase transitions of diblock copolymer mixtures, revealing complex structural transformations dependent on shear frequency.

Contribution

It provides new insights into the phase behavior of diblock copolymer mixtures under oscillating shear, highlighting the effects of shear frequency and composition on structure formation.

Findings

Phase transitions depend on shear frequency.

Layered structures form perpendicular to each other.

Domain size evolution confirms phase changes.

Abstract

The self-assembly behaviour of a diblock copolymer-diblock copolymer mixture under an oscillating shear field is investigated via cell dynamics simulation. The results indicate that the macrophase separation of the composite system is accompanied by the corresponding microphase separation induced by the oscillating shear field. With an increase in the shear frequency, the AB phase changes from a tilted layered structure to a parallel layered structure, and finally to a vertical layered structure. The CD phase transforms from the initial concentric ring into a parallel layer in the ring and then into a parallel layered structure; thus, the system finally forms a layered structure of the AB phase (vertical layer) and CD phase (parallel layer) perpendicular to each other. To verify the phase transition, the dynamic evolution of the domain size at different shear frequencies is analysed. The ordered phase transition with an increase in the oscillating shear field varies when the initial composition ratio of the system is changed. This conclusion provides a valuable guidance for the formation and transformation of ordered structures in experiments.