From Chitosan to Chitin : Bio-Inspired Thin Films for Passive Daytime Radiative Cooling

Titelangaben

Lauster, Tobias ; Mauel, Anika ; Herrmann, Kai ; Veitengruber, Viktoria ; Song, Qimeng ; Senker, Jürgen ; Retsch, Markus:
From Chitosan to Chitin : Bio-Inspired Thin Films for Passive Daytime Radiative Cooling.
In: Advanced Science. Bd. 10 (2023) Heft 11 . - 2206616.
ISSN 2198-3844
DOI der Verlagsversion: https://doi.org/10.1002/advs.202206616

Volltext

	Format: PDF Name: Advanced Science - 2023 - Lauster - From Chitosan to Chitin Bio‐Inspired Thin Films for Passive Daytime Radiative Cooling.pdf Version: Veröffentlichte Version Verfügbar mit der Lizenz Creative Commons BY 4.0: Namensnennung
	Download (2MB)

Abstract

Passive radiative daytime cooling is an emerging technology contributing to carbon-neutral heat management. Optically engineered materials with distinct absorption and emission properties in the solar and mid-infrared range are at the heart of this technology. Owing to their low emissive power of about 100 W m(-2) during daytime, substantial areas need to be covered with passive cooling materials or coatings to achieve a sizeable effect on global warming. Consequently, biocompatible materials are urgently needed to develop suitable coatings with no adverse environmental impact. It is shown how chitosan films with different thicknesses can be produced from slightly acidic aqueous solutions. The conversion to their insoluble form chitin in the solid state is demonstrated and the conversion is monitored with infrared (IR) and NMR spectroscopy. In combination with a reflective backing material, the films show below-ambient temperature cooling capabilities with a suitable emissivity in the mid-IR region and low solar absorption of 3.1-6.9%, depending on the film thickness. This work highlights the potential of chitosan and chitin as widely available biocompatible polymers for passive radiative cooling applications.