Enhancing the thermal conductivity in electrocaloric polymers by structural orientation for collaborative thermal management

Endowing bulk electrocaloric polymers with excellent thermal conductivity is a superior solution to the high-efficient and precise management of tremendous heat from high-power-density electronic devices. Semi-crystalline polymer P(VDF-TrFE-CFE), i.e., poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene), has a predominant amorphous phase of randomly entangled chains and abundant interface, leading to localized behavior in phonon heat conduction and thereby low thermal conductivity. To enhance the thermal transport performance, electrocaloric polymer films were mechanically stretched or fabricated by electrospun to achieve highly aligned molecular chains. Chain orientation brought about a 2.4- and 1.6-times increase in the thermal diffusion coefficient of the stretched and electrospun films, respectively. Interestingly, after mechanical stretching, the thermal conductivity of the film was increased by a factor of two. In contrast, the electrospun film had a slightly lower thermal conductivity than that of the unoriented one. A remarkable discrepancy in the electrocaloric properties was observed, where the stretched polymer film reached a much higher adiabatic temperature change under an applied electric field than that of the electrospun film. Our strategy provides a perspective on designing a promising thermal management system through the integration of active refrigeration and passive heat dissipation in bulk electrocaloric polymers.

Automated summary

Endowing bulk electrocaloric polymers with excellent thermal conductivity is an effective solution for managing the heat generated by electronic devices. By mechanically stretching or electrospinning the polymer films, the alignment of molecular chains can be improved to enhance thermal transport performance. The thermal conductivity of the stretched film increased by a factor of two, while the electrospun film had a slightly lower thermal conductivity than the unoriented one. The stretched film exhibited a significantly higher adiabatic temperature change under an applied electric field compared to the electrospun film. This study provides a perspective on designing a promising thermal management system through integrating active refrigeration and passive heat dissipation in bulk electrocaloric polymers.