Thermal conductivity of bottle-brush polymers

TL;DR

This study uses molecular dynamics simulations to explore how the architecture of bottle-brush polymers affects their thermal conductivity, revealing a non-monotonic relationship influenced by grafting density and side chain properties.

Contribution

It provides new insights into the competing effects of backbone stiffness and side chain pathways on heat transfer in bottle-brush polymers.

Findings

Thermal conductivity varies non-monotonically with grafting density.

Backbone stiffness and side chains have competing effects on heat flow.

Side chain mass influences heat transfer in polymer melts.

Abstract

Using molecular dynamics (MD) simulations of a generic model, we investigate heat propagation in bottle--brush polymers (BBP). An architecture is referred to as a BBP when a linear (backbone) polymer is grafted with the side chains of different length $N_{\rm s}$ and grafting density $\rho_{\rm g}$, which control the bending stiffness of a backbone. A BBP is of particular interest due to two competing mechanics: increased backbone stiffness, via $N_{\rm s}$ and $\rho_{\rm g}$, increases the thermal transport coefficient $\kappa$, while the presence of side chains provides additional pathways for heat leakage. We show how a delicate competition between these two effects controls $\kappa$. These results reveal that going from a weakly grafting ($\rho_{\rm g} < 1$) to a highly grafting ($\rho_{\rm g} \ge 1$) regime, $\kappa$ changes non--monotonically that is independent of $N_{\rm s}$. The effect of side chain mass on $\kappa$ and heat flow in the BBP melts are also discussed.