Reversible transition between isotropic and anisotropic thermal transport in elastic polyurethane foams

Abstract

Elastic composite foams with anisotropic lamellar microstructures were formed by freeze-casting polyurethane dispersions with graphitic additives. This anisotropy resulted in orientation-dependent mechanical and thermal properties. Most importantly, the effective thermal conductivity can be reversibly transitioned between anisotropic and isotropic states by altering the thermal conductivity of the contained atmosphere.