Design, Fabrication, and Analysis of a Capillary Diode for Potential Application in Water–Oil Separation

Abstract

A capillary device is designed and fabricated in glass to work as a fluidic diode with vanishingly small hydrodynamic conductance for imbibition of water within a finite range of immersion depths. This is attained through patterning a section of predefined length on the device surfaces using a single-step laserbased ablation process and without resorting to chemical treatment of the hydrophilic glass substrate. While the studied device works as a fluidic diode for water, it can behave as a conventional capillary slit for the imbibition of oils (e.g., alkanes, silicone oils) with low surface tension. A prototype device with simple geometric design is demonstrated for selective adsorption and separation of water and oil in vertical imbibition experiments at controlled immersion depths. Efficient devices for passive separation of water and oil can be designed based on the demonstrated physical mechanism and the analytical model proposed in this work.

Phase separation of an ionic liquid mixture assisted by a temperature gradient

“…The present paper paves a way in binary mixture recycling. The impact of UCST behavior and spatial patterning in the cavity will be the object of future works [55][56][57][58]. The thickness variation of the wetting film is difficult to quantify with confocal experiments, but interferometric methods allow us to obtain at least one relative variation in height between two points [59].…”

Robust and durable liquid-repellent surfaces

“…Additionally, 1D resolution of surface wettability along the advancing/receding direction can be achieved by the Wilhelmy technique. This method is much preferred for CA measurement of plain plate, 132,133 fabric 134 and fiber 135 with rectangular or cylindrical shapes (i.e., a constant perimeter) and same chemistries in both sides. For samples with different wettability on the two sides, back-to-back bonding is suggested to expose two same surfaces for measurement.…”

Wetting ridges on slippery liquid-infused porous surfaces

“…Slippery liquid-infused porous surfaces (SLIPS) represent a unique class of liquid-repellent surfaces made of a porous scaffold and a lubricant layer stabilized within and above the surface of the porous scaffold [1,2]. SLIPS offer useful functions for various key applications, including self-cleaning [3,4], anti-icing [5][6][7], anti-fouling [8][9][10][11][12][13], corrosion-resistant [14,15], food packaging [16,17], wave guiding [18], separations [19], heat transfer enhancing [20][21][22][23], drag-reducing [24][25][26], and water harvesting coatings [27][28][29][30][31]. The remarkable liquid repellency of SLIPS originates from the lubricant layer infused into the porous scaffold [32,33].…”