PROFESSOR @ ETH ZURICH
The nanoscale design of sunlight-surface interactions to harness (enhance or deter) atmospheric water vapor condensation
Interfaces separating different kinds of matter, or different phases of the same matter, abandon in nature and technology. What is more, they invariably play a critical role in all systems where they occur, from regulating transport of energy and species, to dictating system shape and form. Interfaces differ in their structure and properties from the bulk matter they surround. I note here the famous quote of Wolfgang Pauli that “God made bulk (materials) but surfaces are the work of the devil”. In this lecture I will primarily focus on liquid/gas and liquid/solid interfaces, as they manifest themselves in simple systems, specifically here in condensation applications, which play a significant role in the performance of a broad pallet of technologies.
I will describe phenomena ranging from (unwanted) fogging of transparent objects to direct water harvesting from the atmospheric air. I will present results on how the science of harvesting sunlight through rationally engineered (meta)surfaces and devices, can enable the harnessing of this unparalleled renewable energy source, to reach unprecedented performance levels. Antifogging is readily achieved with photothermal plasmonic coatings maintaining surface transparency. In solar driven water harvesting, utilizing radiative cooling to the outer space with optimized radiation shielding, coupled with a fully passive nanostructures superhydrophobic condensate harvester, yields uninterrupted water harvesting; not only during night-time but also during daytime.