A biomimicry design for nanoscale radiative cooling applications inspired by Morpho didius butterfly

Abstract

In nature, novel colors and patterns have evolved in various species for survival, recognizability or mating purposes. Investigations of the morphology of various butterfly wings have shown that in addition to the pigmentation, micro and nanostructures within the wings have also allowed better communication systems and the pheromone-producing organs which are the main regulators of the temperature within butterfly wings. Within the blue spectrum (450–495 nm), Morpho didius butterfly exhibit iridescence in their structure-based wings’ color. Inspired by the rich physics behind this concept, we present a designer metamaterial system that has the potential to be used for near-field radiative cooling applications. This biomimicry design involves SiC palm tree-like structures placed in close proximity of a thin film in a vacuum environment separated by nanoscale gaps. The near-field energy exchange is enhanced significantly by decreasing the dimensions of the tree and rotating the free-standing structure by 90 degrees clockwise and bringing it to the close proximity of a second thin film. This exchange is calculated by using newly developed near-field radiative transfer finite difference time domain (NF-RT-FDTD) algorithm. Several orders of enhancement of near-field heat flux within the infrared atmospheric window (8–13 μm bandwidth) are achieved. This spectrally selective enhancement is associated with the geometric variations, the spatial location of the source of excitation and the material characteristics, and can be tuned to tailor strong radiative cooling mechanisms.

Biologically inspired flexible photonic films for efficient passive radiative cooling

“…One of the fascinating phenomena is structural whiteness or silver color, which can be prevalently found in insects (33)(34)(35), aquatic organisms (36,37), and mammals (38,39). Over the past few years, numerous biological creatures have been reported to exhibit a thermal regulation ability (40)(41)(42)(43)(44). For example, silvery Saharan ants were reported to exhibit thermal control behaviors via their triangularshaped hairs, which exhibited high reflectivity in the visible to near-infrared (vis-NIR) region and high emissivity in the midinfrared (MIR) region (40).…”

Heat transfer properties of Morpho butterfly wings and the dependence of these properties on the wing surface structure

“…21 Didari et al suggested a way to design original and modied structures of Morpho didius wings using algorithms. 22 This report revealed that the heat ux within the atmospheric window (8-13 mm bandwidth) of the simulated structures varied by changing the distance between the shelves and their sizes. We speculate that the ridges and lamellae structures of Morpho buttery wings would act as effective paths for heat transfer, and changes in the surface structure would affect the radiative heat ux.…”

Holographic Sensors in Biotechnology

“…Reproduced with permission. [131] Copyright 2018, Springer Nature; ii) Transmission electron microscopy (TEM) image of wing scales of a Morpho butterfly, iii) Morpho butterfly wing as observed in the wild (top), Morpho butterfly wing treated with ethanol (bottom). Reproduced under the terms and conditions of the Creative Commons Attribution (CC BY) license.…”