Structure of bottle-brush brushes under good solvent conditions. A molecular dynamics study

TL;DR

This study uses molecular dynamics simulations to analyze the structure and properties of bottle-brush polymers grafted on a rigid backbone under good solvent conditions, revealing how their complex architecture influences their behavior.

Contribution

It provides the first detailed simulation-based characterization of bottle-brush polymers with a standard bead-spring model under good solvent conditions.

Findings

End beads are excluded from the region near the backbone due to side chains.

Multiple correlation lengths exist due to complex structure.

Properties can be precisely tuned in good solvents.

Abstract

We report a simulation study for bottle-brush polymers grafted on a rigid backbone. Using a standard coarse-grained bead-spring model extensive molecular dynamics simulations for such macromolecules under good solvent conditions are performed. We consider a broad range of parameters and present numerical results for the monomer density profile, density of the untethered ends of the grafted flexible backbones and the correlation function describing the range that neighboring grafted bottle-brushes are affected by the presence of the others due to the excluded volume interactions. The end beads of the flexible backbones of the grafted bottle-brushes do not access the region close to the rigid backbone due to the presence of the side chains of the grafted bottle-brush polymers, which stretch further the chains in the radial directions. Although a number of different correlation lengths exist as a result of the complex structure of these macromolecules, their properties can be tuned with high accuracy in good solvents. Moreover, qualitative differences with "typical" bottle-brushes are discussed. Our results provide a first approach to characterizing such complex macromolecules with a standard bead spring model.