Microphase separation in linear multiblock copolymers under poor solvent conditions

TL;DR

This study uses molecular dynamics simulations to explore how linear multiblock copolymers with two monomer types behave under poor solvent conditions, revealing temperature-dependent phase separation and clustering behaviors.

Contribution

It provides a detailed analysis of the phase behavior of symmetrical multiblock copolymers under varying temperature and solvent quality, highlighting cluster formation mechanisms.

Findings

At high temperatures, copolymers form coil structures with separate A and B clusters.

At low temperatures, A and B monomers from different blocks form mixed clusters.

The phase behavior depends on temperature, block length, and number of blocks.

Abstract

Molecular dynamics simulations are used to study the phase behavior of linear multiblock copolymers with two types of monomers, A and B, where the length of the polymer blocks $N_{A}$ and $N_{B}$ ($N_{A}=N_{B}=N$), the number of the blocks $n_{A}$ and $n_{B}$ ($n_{A}=n_{B}=n$), and the solvent quality varies. The fraction $f$ of A-type monomers is kept constant and equal to 0.5. Whereas at high enough temperatures these macromolecules form coil structures, where each block A or B forms rather individual clusters, at low enough temperatures A and B monomers from different blocks can join together forming clusters of A or B monomers. The dependence of the formation of these clusters on the varied parameters is discussed in detail, providing a full understanding of the phase behavior of linear multiblock copolymers, at least for this symmetrical case.