Flexible passive radiative cooling inspired by Saharan silver ants

Saharan silver ants can inhabit one of the hottest areas, the Sahara Desert, which benefits from their thermoregulatory functionality, thanks to a sophisticated photonic structure of hairs. Mimicking the photonic structure, we fabricated the flexible hair-like photonic structures on polydimethylsiloxane (PDMS). Attaching them to glass bottles for a proof-of-concept demonstration, the considerably enhanced optical reflection was observed as well as the slightly improved mid-infrared emission. These extraordinary properties enabled the temperature of the glass bottles to be reduced by around 5.6 degrees C in the hot daytime and keep relatively warm in the cold nighttime. On the basis of optical and thermal properties of the silver ants-inspired photonic structures, potential applications could be further found in wearable devices and personal thermal management.