Effects of Hydrophobicity-Inducing Roughness on Micro-Flows

Heck, Margaret; Papavassiliou, Dimitrios V.

doi:10.1080/00986445.2012.729543

Cited by 8 publications

(2 citation statements)

References 44 publications

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“…Understanding dynamic wetting behaviour is important for a vast range of applications such as industrial processes, coating and painting technology (Joanny and de Gennes 1984, Pomeau and Vannimenus 1985, Lafuma and Quere 2003, He et al 2004, Ou et al 2004, Bhushan and Jung 2007, Daniello et al 2009, Dorrer and Ruhe 2009, Heck and Papavassiliou 2013, Smyth et al 2013, Mohammad Karim et al 2016b, 2017a, 2017b, 2018b, 2018c, 2018d, 2019, 2020, Abe et al 2017. If the thickness of the liquid film can be controlled, the coating and painting processes would be optimized in terms of the speed and the quality.…”

Section: Introductionmentioning

confidence: 99%

Contact line dynamics of gravity driven spreading of liquids

Karim

Fujii

Kavehpour³

2021

Fluid Dyn. Res.

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The spreading dynamics of the gravity-driven liquid motion on an inclined solid surface was studied by considering two fundamental physical models: the molecular kinetic theory and the hydrodynamic theory (HDT). The molecular kinetic theory is the most appropriate model to describe the gravity driven spreading mechanism investigated in this study. The gravity driven spreading which is one form of the forced spreading mechanism was compared with the spontaneous spreading for the same liquid/solid system from previous study by Mohammad Karim et al (2016 Langmuir 32 10153). Unlike the gravity driven spreading, the HDT was appropriate model to define the spontaneous spreading. This finding reveals the importance of the mechanism of spreading which are the forced and the spontaneous on the suitability of the physical model such as the molecular kinetic theory and the HDT to describe the spreading dynamics.

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Section: Introductionmentioning

confidence: 99%

Contact line dynamics of gravity driven spreading of liquids

Karim

Fujii

Kavehpour³

2021

Fluid Dyn. Res.

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“…This understanding is substantiated by a very recent numerical study, which demonstrated that contrary to the general perception elucidated in the literature, the drag reduction for microscale ows, through channels with microposts (articial roughness) on the walls, is restricted by a critical micro-connement conguration, even within the low Reynolds number paradigm. 22 From the above discussions, we may reach a consensus that there is an overwhelming need for a critical assessment of the biomimetic, superhydrophobic wall mediated microscale hydrodynamics not only from an engineering perspective, but also from a scientic standpoint for unambiguously comprehending the underlying physics dictating such microows. To comprehensively address this issue, the present work delineates the hydrodynamic characteristics of water ows through rectangular microchannels with a lotus leaf replica wall.…”

Section: Introductionmentioning

confidence: 99%

Tunable hydrodynamic characteristics in microchannels with biomimetic superhydrophobic (lotus leaf replica) walls

Dey

Bhandaru

et al. 2014

Soft Matter

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The present work comprehensively addresses the hydrodynamic characteristics through microchannels with lotus leaf replica (exhibiting low adhesion and superhydrophobic properties) walls. The lotus leaf replica is fabricated following an efficient, two-step, soft-molding process and is then integrated with rectangular microchannels. The inherent biomimetic, superhydrophobic surface-liquid interfacial hydrodynamics, and the consequential bulk flow characteristics, are critically analyzed by the micro-particle image velocimetry technique. It is observed that the lotus leaf replica mediated microscale hydrodynamics comprise of two distinct flow regimes even within the low Reynolds number paradigm, unlike the commonly perceived solely apparent slip-stick dominated flows over superhydrophobic surfaces. While the first flow regime is characterized by an apparent slip-stick flow culminating in an enhanced bulk throughput rate, the second flow regime exhibits a complete breakdown of the aforementioned laminar and uni-axial flow model, leading to a predominantly no-slip flow. Interestingly, the critical flow condition dictating the transition between the two hydrodynamic regimes is intrinsically dependent on the micro-confinement effect. In this regard, an energetically consistent theoretical model is also proposed to predict the alterations in the critical flow condition with varying microchannel configurations, by addressing the underlying biomimetic surface-liquid interfacial conditions. Hence, the present research endeavour provides a new design-guiding paradigm for developing multi-functional microfluidic devices involving biomimetic, superhydrophobic surfaces, by judicious exploitation of the tunable hydrodynamic characteristics in the two regimes.

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