Lotus leaf-inspired thermal insulation and anti-icing topography

Abstract

Porous sandwich-like structures with surface roughness possess the capacity to sustain droplets, diminish the area of contact between solids and liquids, and augment heat conductivity, and thus delay ice formation when the temperature drops below the freezing point. The prevalence of this combination of surface roughness and a hollow sandwich structure has been observed in several organisms, such as lotus leaves, which have developed these features as a result of environmental adaptation. This study introduces a new design for a surface consisting of a micro–nano conical array and a foam structure with a gradient of pores. The primary components of this design were isocyanate and polyether. The hollow gradient sandwich structure was created by manipulating the water content to increase the porosity, resulting in the formation of a conical–pit morphology on the underside of the specimen. This configuration significantly decreased the amount of heat lost and the modulus of elasticity of the sample. Additionally, the micro–nano hydrophobic structure on the upper surface hindered the transmission of temperature and delayed the formation of ice. This concept, inspired by natural structures, has significant potential applications in the areas of anti-icing, energy conservation, and environmental preservation.