Polymer–nanoparticle networks have potential applications
in molecular electronics and nanophononics. In this work, we use all-atom
molecular dynamics to reveal the fundamental mechanisms of thermal
transport in polymer-linked gold nanoparticle (AuNP) dimers at the
molecular level. Attachment of the polymers to AuNPs of varying sizes
allows the determination of effects from the flexibility of the chains
when their ends are not held fixed. We report heat conductance (G) values for six polymersviz. polyethylene, poly(p-phenylene), polyacene, polyacetylene, polythiophene, and
poly(3,4-ethylenedioxythiophene)that represent a broad range
of stiffness. We address the multimode effects of polymer type, AuNP
size, polymer chain length, polymer conformation, system temperature,
and number of linking polymers on G. The combination
of the mechanisms for phonon boundary scattering and intrinsic phonon
scattering has a strong effect on G. We find that
the values of G are larger for conjugated polymers
because of the stiffness in their backbones. They are also larger
in the low-temperature region for all polymers owing to the quenching
of segmental rotations at low temperature. Our simulations also suggest
that the total G is additive as the number of linking
polymers in the AuNP dimer increases from 1 to 2 to 3.