Materials with responsive thermal conductivities allow for active control of heat flow, which is important for heat management applications including waste heat recovery and refrigeration. To achieve dynamic control of the thermal conductivity, a material’s heat capacity or thermal diffusivity may be changed in response to an external stimulus (<i>e.g.</i> heat, light). Polymeric materials are promising because they can be rendered sensitive to external stimuli in a straight-forward manner and often function at low operating temperatures. However, they generally exhibit low thermal conductivities due to weak intermolecular forces. Due to the lack of long-range periodic order, a fundamental understanding of structure/property interrelations is difficult to establish. We exploit here the reversible conversion of a monomeric dye to a polymer to elucidate if a polymerization process results in a responsive thermal conductivity. We demonstrate that the monomer-to-polymer conversion leads to changes in the material’s optical and thermal transitions yet does not change its thermal conductivity. This is likely due to the small conformational changes that occur during polymerization leading to negligible differences in heat capacity and thermal diffusivity. Our work thus provides insights towards designing materials systems with dynamic control of the thermal conductivity upon exposure to external stimuli.

Thermal conductivity is independent of topochemical polymerization in organic materials

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.