Computer simulation of bottle brush polymers with flexible backbone: Good solvent versus Theta solvent conditions

Abstract

By Molecular Dynamics simulation of a coarse-grained bead-spring type model for a cylindrical molecular brush with a backbone chain of $N_b$ effective monomers to which with grafting density $\sigma$ side chains with $N$ effective monomers are tethered, several characteristic length scales are studied for variable solvent quality. Side chain lengths are in the range $5\le N\le 40$, backbone chain lengths are in the range $50\le N_b\le 200$, and we perform a comparison to results for the bond fluctuation model on the simple cubic lattice (for which much longer chains are accessible, $N_b\le 1027$, and which corresponds to an athermal, very good, solvent). We obtain linear dimensions of side chains and the backbone chain and discuss their $N$-dependence in terms of power laws and the associated effective exponents. We show that even at the Theta point the side chains are considerably stretched, their linear dimension depending on the solvent quality only weakly. Effective persistence lengths are extracted both from the orientational correlations and from the backbone end-to-end distance; it is shown that different measures of the persistence length (which would all agree for Gaussian chains) are not mutually consistent with each other, and depend distinctly both on $N_b$ and the solvent quality. A brief discussion of pertinent experiments is given.

30 pages, 13 figures, 1 table

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Cited by in corpus (8)

• Hierarchical excluded volume screening in solutions of bottlebrush polymers
• Spontaneous helicity of a polymer with side-loops confined to a cylinder
• Molecular dynamics simulations of single-component bottle-brush polymers with a flexible backbone under poor solvent conditions
• Structure of bottle-brush brushes under good solvent conditions. A molecular dynamics study
• Thermal conductivity of polymers: A simple matter where complexity matters
• Patchy worm-like micelles: solution structure studied by small-angle neutron scattering
• A study for the static properties of symmetric linear multiblock copolymers under poor solvent conditions
• Phase behaviour of two-component bottle-brush polymers with flexible backbones under poor solvent conditions