LAUSR

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, TT, the aerogel- SiO 2 composite thermal conductance will increase by more than 100×. Using approaches based on Kirchhoff's 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.