Amorphous polymers are soft materials whose thermal properties are dominated by weak, nonbonded interactions that strongly suppress heat flow, limiting the thermal transport coefficient, κ, to below 0.40 W m-1 K-1. Recent experiments, however, show that electrostatic modification of poly(acrylic acid) (PAA) can increase κ beyond 1.00 W m-1 K-1 in highly ionized systems, compared to κ ≃ 0.33 W m-1 K-1 for uncharged PAA. Using molecular-dynamics simulations of a bead-spring polymer model, we study the effect of ionization on κ in amorphous polymers. In agreement with experiment, we observe a more than 2.5-fold enhancement in κ, driven by electrostatically induced, local chain stiffening that increases the bonded contribution to κ. These results identify a generic mechanism for tuning κ across a broad class of charged polymers.
Mukherji et al. (Wed,) studied this question.