Stroock Research Group work published in Physical Review Letters and News & Views in Nature Materials
Drying from porous media is a very common phenomenon, with examples of increasing importance such as drying of soils and plants during drought, or drying of rocks subsequent to underground gas flow. Understanding and predicting drying in these examples is particularly challenging due to the large range of lengthscales that coexist in the porous medium, which can span from nanometers to meters.
Inspired by the structures of the water conducting tissues that can be found in trees, a team in Abraham Stroock’s group built artificial porous structures (in glass and silicon) with two well separated length scales: voids or channels at the micrometer scale that are interconnected by pores only a few nanometers wide.
They showed that drying from these “ink-bottle” structures does not proceed by receding of the air-liquid interface from the edges, but occurs by discrete and sudden bubble nucleation (cavitation) events far from the edges. They further showed that the coupling between the nucleation kinetics and transient transport of liquid in the nanopores resulted in non-monotonic drying with quasi-periodic “bursts” of emptying events and spatial correlations of the dried zones.
In addition to presenting a simple, original model system exhibiting unusual reaction-diffusion kinetics entailing spatio-temporal pattern formation, the study opens new perspectives on our understanding of the way plants respond to drought or on predictions of gas pocket formation during the sequestration of carbon dioxide in the geological subsurface.
These results were recently published in Physical Review Letters  and are the subject of a News & Views in Nature Materials .
 Vincent, O. et al., Physical Review Letters, 2014, vol. 113, p. 134501 (link: http://dx.doi.org/10.1103/PhysRevLett.113.134501)
 Ball, P., Nature Materials, 2014, vol. 13, p. 922 (link: http://dx.doi.org/10.1038/nmat4095)