Thermal Conductivity of Bottle-Brush Polymers

Using molecular dynamics (MD) simulations of a generic model, we investigated 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-s and grafting density rho(g), which control the bending stiffness of a backbone. Investigating kappa-behavior in BBP is of particular interest due to two competing mechanics: increased backbone stiffness, via N-s and rho(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(g) < 1) to a highly grafting (rho(g) >= 1) regime, kappa changes non-monotonically that is independent of N-s. The effect of side chain mass on kappa and heat flow in the BBP melts is also discussed.