Penn Engineers Discover a New Class of Materials That Passively Harvest Water from Air
May 26th, 2025Via: University of Pennsylvania:
A serendipitous observation in a Chemical Engineering lab at Penn Engineering has led to a surprising discovery: a new class of nanostructured materials that can pull water from the air, collect it in pores and release it onto surfaces without the need for any external energy.
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When water condenses on surfaces, it usually requires either a drop in temperature or very high humidity levels. Conventional water harvesting methods rely on these principles, often requiring energy input to chill surfaces or a dense fog to form to collect water passively from humid environments. But Lee and Patel’s system works differently.
Instead of cooling, their material relies on capillary condensation, a process where water vapor condenses inside tiny pores even at lower humidity. This is not new. What is new is that in their system, the water doesn’t just stay trapped inside the pores, as it usually does in these types of materials.
“In typical nanoporous materials, once the water enters the pores, it stays there,” explains Patel. “But in our material, the water moves, first condensing inside the pores, then emerging onto the surface as droplets. That’s never been seen before in a system like this, and at first we doubted our observations.”
Paper: Amphiphilic nanopores that condense undersaturated water vapor and exude water droplets
