Thermal conductance switching in aerogel-SiO_2 nanoparticle composites

摘要

In this Letter, we theoretically describe the dramatic conductance switching properties of a smart aerogel containing phonon polariton (PhP)-supporting nanoparticles with variable dispersity. When its temperature is greater than a transition temperature, T_T, the aerogel-SiO_2 composite thermal conductance will increase by more than 100 ×. Using approaches based on Kirchhoffs laws and the fluctuation dissipation theorem, we show that the thermal conductance switching emerges from the nanometer-scale displacements of nanoparticles entrained in the volumetric changes of the smart aerogels and the d~(-6) dependence of nanoparticle PhP radiation heat exchange on the separation distance, d.