  The phase behaviour of two-component bottle-brush polymers with fully
flexible backbones under poor solvent conditions is studied via
molecular-dynamics simulations, using a coarse-grained bead-spring model and
side chains of up to $N=40$ effective monomers. We consider a symmetric model
where side chains of type A and B are grafted alternately onto a flexible
backbone. The aim of this study to explore the phase behaviour of two-component
bottle-brushes depending on parameters, such as as the grafting density
$\sigma$, the backbone length $N_b$, the side-chain length $N$, and the
temperature $T$. Based on a cluster analysis, we identify for our range of
parameters the regimes of fully phase separated systems, i.e., A-type side
chains form one cluster and B-type chains another, while the interface that
separates these two clusters contains the backbone monomers. We find that
pearl-necklace or Janus-like structures, which normally occur for bottle-brush
polymers with rigid backbones under poor solvent conditions, are fully
attributed to the backbone rigidity, and, therefore, such structures are
unlikely in the case of bottle brushes with fully flexible backbones. Also, a
comparative discussion with earlier work on the phase behaviour of
single-component bottle-brush polymers with flexible backbones is performed.

Soft Condensed Matter