Researchers at Stanford University in the US have created a bilayer material comprising a micrometre-scale sheet of carbon, which emits radiation effectively, coupled with a copper layer, which is a very poor emitter.
Dual-mode textile morphology and emissivity characterization.
(A) Image of a carbon-coated nanoPE, the high-emissivity layer. (B) SEM image of carbon coating reveals its rough and porous structure, which is advantageous for increasing the emissivity. (C) Image of a copper-coated nanoPE, the low-emissivity layer. (D) SEM image of copper coating shows that the surface is optically smooth for mid-IR. The nanopores remain open for air and vapor permeability. (E) Layered structure of the dual-mode textile. Note that the nanoPE on the side of carbon is thicker than the copper side. Note that all the materials are porous to allow air and vapor breathability. (F) Emissivities of carbon and copper coating, as measured by FTIR equipped with a diffuse gold integrating sphere.