Fig. 4: Optical properties of ACA.
From: Scalable anisotropic cooling aerogels by additive freeze-casting
a Solar reflection spectra of commercial EPS foam, SiO2 aerogel with and without a high-reflective coating, and ACA. The measured solar reflectances of commercial EPS foam, SiO2 aerogel with and without a high-reflective coating, and ACA are 79%, 85%, 81% and 97%, respectively. b Effect of porosity on average reflectance of pristine WPU aerogels estimated from the FDTD simulations. c Simulated reflection spectra of highly porous WPU aerogels with and without BNNS. d Comparison of the solar reflectance and thermal conductivity of ACA with those of strate-of-the-art thermally insulating materials reported in the literature21,22,23,61,62,63,64,65,66 and commercial products (i.e., SiO2 and EPS foam). Schematics of the multiscale mechanisms of extensive light scattering by (e) solid/air interfaces due to a highly porous structure, (f) BNNS/WPU interfaces because of the contrasting refractive indices, and (g) reduced NIR absorption because of BNNS. The atoms in orange, green, blue, red and grey colours represent boron, nitrogen, oxygen, hydrogen and carbon, respectively.
