Switching MIR absorption with Water
My research focuses on the development of water-driven, mid-infrared (MIR) switchable polymer aerogels with dynamically tunable optical properties. Conducted within the Exzellenzcluster BlueMat – Water-Driven Materials (funded by the Deutsche Forschungsgemeinschaft, DFG), the project combines porous materials science, photonics, and thermodynamics.
The research involves the synthesis of nanoporous polymer aerogels using cryogenic and supercritical drying techniques, followed by systematic investigation of water adsorption and confinement phenomena through thermodynamic, spectroscopic, and scattering methods. The central concept is a water-induced switching of radiative heat transfer. In the dry state, the aerogel is transparent in the 8–13 µm range, enabling radiative cooling. When water is adsorbed, MIR absorption increases, suppressing heat loss and switching the material to an insulating state.
This concept enables applications such as programmable thermal facades, where buildings can be cooled at night in the dry state and insulated during the day in the water-loaded state. Beyond building applications, the materials offer potential for integrated thermal management systems synchronized with energy availability, as well as enhanced dew harvesting through controlled sub-dew-point cooling and reduced re-evaporation.
