Micropattern-controlled wicking enhancement in hierarchical micro/nanostructures

Abstract

Micropattern-controlled two-stage wicking dynamics dictate the enhancement of wicking in hierarchical micro/nanostructured surfaces over bare microstructures.

Fast Capillary Wicking on Hierarchical Copper Nanowired Surfaces with Interconnected V-Grooves: Implications for Thermal Management

“…More recently, the enhancement of the capillary wicking capability has been demonstrated by coupling nanostructures and microstructures on the hierarchical structured surfaces. Hierarchical structures reported recently include nanocactus arrays, 35 micropillars with nanowires, 36 nanorods on micropillars, 37 and nanoporous micropillared surfaces. 38 The hierarchical structures show faster wicking speed compared to single-scaled structures, which is due to the additional capillary pressure by nanostructures and the minimized viscous resistances by microstructures.…”

Advances in Boiling Heat Transfer Enhancement using Micro/Nano Structured Surfaces

“…This typical example can be considered as a base line for studying capillary flow in micro/nano structured surface in association with phase change heat transfer enhancement. Similar concept for studying the magnitude of liquid spread/rise has been applied and proved experimentally and computationally by various researchers [15][16][17][18][19][20][21][22][23] which is elaborated in Table I.…”

Predicting Hemiwicking Dynamics on Textured Substrates

“…They observed that the wetting of this particle induced the formation of a meniscus at its base and the high capillary pressure (∼curvature) of this meniscus locally accelerated contact line motion by a factor of 100 . Increased liquid propagation speeds have also been observed for both regular textures and hierarchical multiscale textures. , Interestingly, the local acceleration and deceleration on textured substrates yield a z ∼ t 1/2 ( t , time) scaling with macroscopic propagation distance ( z ). In contrast, the spreading distance on a flat, smooth surface is known to follow Tanner’s law, z ∼ t 1/10 .…”

“…6 Increased liquid propagation speeds have also been observed for both regular textures 5 and hierarchical multiscale textures. 8,9 Interestingly, the local acceleration and deceleration on textured substrates yield a z ∼ t 1/2 (t, time) scaling with macroscopic propagation distance (z). In contrast, the spreading distance on a flat, smooth surface is known to follow Tanner's law, z ∼ t 1/10 .…”

“…It is an important surface science phenomenon critical to applications ranging from inkjet printing to liquid hydrocarbon recovery. While wicking broadly describes liquid propagation through a three-dimensional (3D) porous medium, hemiwicking is the spreading of a liquid on a textured surface where the wetting of dry regions is accompanied by the increase of the liquid–air interfacial area. , Interest in hemiwicking was kindled by early studies showing that the addition of texture to smooth substrates significantly enhanced the propagation rates of liquids. , A number of groups have investigated the physics underlying such acceleration by textural addition. − For instance, Ueno et al studied the dynamics of interaction of a planar three-phase (solid, liquid, air) contact line with a single microparticle. They observed that the wetting of this particle induced the formation of a meniscus at its base and the high capillary pressure (∼curvature) of this meniscus locally accelerated contact line motion by a factor of 100 .…”