Understanding the thermal conductivity in metal–organic
framework (MOF)-polymer composites is crucial for optimizing their
performance in applications involving heat transfer. In this work,
several UiO66-polymer composites (where the polymer is either PEG,
PVDF, PS, PIM-1, PP, or PMMA) are examined using molecular simulations.
Our contribution highlights the interface’s impact on thermal
conductivity, observing an overall increasing trend attributable to
the synergistic effect of MOF enhancing polymer thermal conductivity.
Flexible polymers such as PEG and PVDF exhibit increased compatibility
with the MOF, facilitating their integration with the MOF lattice.
However, this integration leads to a moderated enhancement in thermal
conductivity compared to polymers that remain separate from the MOF
structure, such as PS or PP. This effect can be attributed to alterations
in phonon transport pathways and shifts in interfacial interactions
between the polymer and MOF. Specifically, the infiltration of the
polymer like PEG and PVDF into the MOF disrupted the MOF’s
ordered network, introducing defects or barriers that hindered phonon
propagation. In contrast, nonpolar and rigid polymers like PP, PMMA,
PS, and PIM-1 exhibited greater improvements in thermal conductivity
when combined with MOFs compared to the flexible polymers PVDF and
PEG. Most notably, our analysis identifies a critical interface region
within approximately 30–50 Å that profoundly influences
thermal conductivity. The interface region, as indicated by the density
profile and radius of gyration, is notably shorter but plays a pivotal
role in modulating the thermal properties. The sensitivity of the
system to these interface characteristics underscores the crucial
role of this particular interface area in dictating the thermal conductivity.
Our findings emphasize the sensitivity of thermal conductivity in
polymer matrices to interface characteristics and highlight the critical
role of a specific interface region in modulating thermal properties.
