Researchers discover a new approach to harvesting moisture from the air using organic crystals

Researchers from the Smart Materials Lab (SML) and Center for Smart Engineering Materials (CSEM) at NYU Abu Dhabi (NYUAD) have reported a novel method for harvesting water from naturally occurring sources such as fog and dew.

In the study, research scientist Patrick Commins and postdoctoral researcher Marieh B. Al-Handawi observed for the first time the process by which water spontaneously condenses from its vapor into a liquid form and moves across the surface of a slowly sublimating organic crystal. This has been found to be caused by changes in the width of small channels that appear on the surface of the crystal over time and conduct the condensed water across the surface of the crystal.

In the article published in the journal entitled “Autonomous and Directional Flow of Water and Transport of Particles across a Subliming Dynamic Crystal Surface”. natural chemistryresearchers describe the process of condensation and movement of water carrying particles on the surface of hexachlorobenzene crystals, a compound commonly used as a fungicide.

Due to sublimation, the surface of this material has a rigid topography with defined parallel channels. It has been observed that small solid particles such as dust or even metallic nanoparticles move autonomously along the channels. The movement of these particles was found to be caused by the condensed air water migrating through the channels due to the change in cross section and width of the channels over time.

Autonomous water flow has previously been achieved using either chemical surface modifications or precisely engineered microchannels or on the surface of natural systems such as some plants or insects. The results of this new study have the potential to guide the development of new technologies to harness naturally occurring water sources, such as dew and fog, which are currently only used by some desert plants and animals for survival.

The new research builds on the understanding of the water collection mechanisms of such biological structures while presenting a fundamentally different mechanism for water transport.

“Motion of water on solid surfaces is one of the most fundamental phenomena in nature,” said Panče Naumov, head of the Smart Materials Lab and director of the Center for Smart Engineering Materials and corresponding author of the study.

“Through thousands of years of evolutionary processes, the surfaces of natural organisms have been optimized for efficient water transport for a variety of life-sustaining functions. Plants do this by moving water against gravity. Our team has discovered a new way to move water across a dynamic solid surface, a fundamentally new underlying principle of water collection. This can be an inspiration for new technologies that could potentially maximize the efficiency of experimental systems used for humidity collection.”