Wettability in complex porous materials, the mixed-wet state, and its relationship to surface roughness

• DOI: 10.1073/pnas.1803734115
• Publication Date: 2018-08-17T21:55:13Z
• Authors: Ahmed AlRatrout; Martin J. Blunt; Branko Bijeljic
• Keywords: Saturation (graph theory)

Significance In many important processes that control <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">C</mml:mi> mathvariant="normal">O</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> storage in aquifers, oil recovery, and gas exchange leaves, for instance, flow is controlled by the interaction of immiscible fluids with a rough surface. We use micrometer-resolution X-ray imaging to look inside millimeter-sized porous structures, obtaining millions measurements contact angle interfacial curvature. quantify relationship between surface roughness wettability. Rougher surfaces are associated lower angles higher curvatures. identify distinct mixed-wet state where two fluid phases remain connected over wide range saturation. This can be designed improve recovery or performance fuel cells, catalysts, other materials.