scholarly journals Fluid contact angle on solid surfaces: Role of multiscale surface roughness

2015 ◽  
Vol 143 (13) ◽  
pp. 134705 ◽  
Author(s):  
F. Bottiglione ◽  
G. Carbone ◽  
B. N. J. Persson
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Solid Surfaces

The Effect of Solid Surface Roughness on Dynamic Contact Angles in Solid-Liquid-Liquid Systems

2002 ◽  
Author(s):  
Dandina N. Rao ◽  
Hussain H. Radwani
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Solid Surface ◽  
Water System ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Liquid Systems ◽  
L Systems ◽  
Solid Liquid

The engineering applications of spreading and adhesion phenomena involving fluids on solids are numerous. The adhesive and spreading interactions at the solid-fluid interfaces are well characterized by dynamic contact angles. This study reports on the results of an experimental investigation into the effect of solid surface roughness on dynamic contact angles in solid-liquid-liquid (S-L-L) systems. The experiment involved the use of Wilhelmy Plate apparatus to measure adhesion tension (which is the product of interfacial tension and cosine of the contact angle between the liquid-liquid interface and the solid surface), the DuNuoy tensiometer to measure the liquid-liquid interfacial tension, and a profilometer to characterize the roughness of the solid surfaces used. The components of the solid-liquid-liquid systems studied consisted of: (i) smooth glass, roughened quartz and an actual rock surface for the solid phase, (ii) normal-hexane and deionized water as the two immiscible liquid phases. The dynamic contact angles (advancing and receding angles) of the three-phase (rock-oil-water) system provide essential information about the wettability of petroleum resrvoirs. The wettability of a reservoir is an important parameter that affects oil recovery in primary, secondary, and enhanced recovery operations [1]. Contact angle measurements on smooth surfaces are generally used to characterize reservoir wettability. However pore surfaces within reservoir rocks are essentially rough and hence it is important to determine the effect of such roughness on measured contact angles. There is very little information in the open literature on the effect of surface roughness on dynamic contact angles in S-L-L systems. In the present work, four levels of roughness of solid surfaces of similar mineralogy (quartz and glass) were tested in hexane-deionized water fluid pair. The advancing and receding contact angles measured at ambient conditions were analyzed for wettability effects. It was found that as surface roughness increased, the dynamic contact angles also increased. The wettability of the rock-oil-water system shifted from weakly water-wet for the smooth glass to intermediate-wet for the roughened surface. The general trends observed in our study were found to be in good agreement with other published results. However, the generally held notion of increasing contact angle hysteresis with increasing roughness appears to be incorrect in solid-liquid-liquid systems.

Measurement Studies on Superhydrophobic Materials

2014 ◽  
Vol 988 ◽  
pp. 134-142
Author(s):  
Sheila Devasahayam ◽  
Prasad Yarlagadda
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Reynolds Number ◽  
Drag Reduction ◽  
Contact Line ◽  
Contact Time ◽  
Contact Angle Hysteresis ◽  
Surface Friction ◽  
Solid Surfaces ◽  
Geometrical Configuration

Superhydrophobicity is directly related to the wettability of the surfaces. Cassie-Baxter state relating to geometrical configuration of solid surfaces is vital to achieving the Superhydrophobicity and to achieve Cassie-Baxter state the following two criteria need to be met: 1) Contact line forces overcome body forces of unsupported droplet weight and 2) The microstructures are tall enough to prevent the liquid that bridges microstructures from touching the base of the microstructures [1]. In this paper we discuss different measurements used to characterise/determine the superhydrophobic surfaces.Keywords: Wettability, contact angle, contact angle hysteresis, contact time, surface roughness, drag reduction measurements, morphology, surface friction, Reynolds number

Tensiometric studies on wetting. I. Some effects of surface roughness (theoretical)

1981 ◽  
Vol 59 (13) ◽  
pp. 1954-1961 ◽  
Author(s):  
Erdal Bayramli ◽  
Theodore G. M. van de Ven ◽  
Stanley G. Mason
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Solid Surfaces ◽  
Surface Slopes ◽  
Receding Contact ◽  
Receding Contact Angle ◽  
Wetting Hysteresis ◽  
Non Equilibrium ◽  
Roughness Size

The effect of roughness on the wettability of an axisymmetric cylinder is investigated theoretically by making use of equilibrium meniscus shapes on solid surfaces analogously to previous studies for drops on horizontal surfaces. Employing circumferential sinusoidal and saw-toothed grooved structure, and using mechanistic arguments, one can explain wetting hysteresis, the formation of composite surfaces, and the presence of non-equilibrium jumps during contact line motion.On unidirectionally random surfaces the maximum surface slopes mainly determine the value of the advancing, and the minimum slopes of the receding contact angle. These effects of surface slopes diminish with decreasing roughness size. Diminishing roughness size also gives rise to numerous small non-equilibrium jumps imposed upon larger jumps during wetting. The contact angle hysteresis is found to show a nearly linear relationship with the spread in the distribution of solid surface slopes.

Liquid Mediated Adhesion of Ultra-Flat Solid Surfaces

1988 ◽  
Vol 119 ◽  
Author(s):  
M. J. Matthewson ◽  
H. J. Mamin
Keyword(s):  
Surface Roughness ◽  
Liquid Film ◽  
Tangential Direction ◽  
Solid Surfaces ◽  
Loading Conditions ◽  
Flat Surfaces ◽  
Separation Rate ◽  
Capillary Condensate

AbstractThe presence of a liquid film between contacting ultra-flat surfaces can produce high levels of adhesion. The liquid film may be a pre-existing film of lubricant or may be a capillary condensate. This paper considers the meniscus and viscous components to the adhesion. Different regimes are identified which are distinguished by differing quantities of liquid in the gap between the surfaces. The role of surface roughness is also evaluated. The force required to separate the surfaces in the tangential direction is considered. The magnitude of this force is dependent not only on the adhesion but also on the separation rate and loading conditions.

Multiple interactions in riverine biofilms - surfactant adsorption, bacterial attachment and biodegradation

1995 ◽  
Vol 31 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Graham F. White
Keyword(s):  
Organic Pollutants ◽  
Bacterial Attachment ◽  
Solid Surfaces ◽  
Sediment Surface ◽  
Liquid Interfaces ◽  
Polluted Soils ◽  
Biofilm Bacteria ◽  
The Impact ◽  
Multiple Interactions

Many organic pollutants, especially synthetic surfactants, adsorb onto solid surfaces in natural and engineered aquatic environments. Biofilm bacteria on such surfaces make major contributions to microbial heterotrophic activity and biodegradation of organic pollutants. This paper reviews evidence for multiple interactions between surfactants, biodegradative bacteria, and sediment-liquid interfaces. Biodegradable surfactants e.g. SDS, added to a river-water microcosm were rapidly adsorb to sediment surface and stimulated the indigenous bacteria to attach to the sediment particles. Recalcitrant surfactants and non-surfactant organic nutrients did not stimulate attachment Attachment of bacteria was maximal when biodegradation was fastest, and was reversed when biodegradation was complete. Dodecanol, the primary product of SDS-biodegradation, markedly stimulated attachment. When SDS was added to suspensions containing sediment and either known degraders or known non-degraders, only the degraders became attached, and attachment accelerated surfactant biodegradation to dodecanol. These cyclical cooperative interactions have implications for the design of biodegradability-tests, the impact of surfactant adjuvants on biodegradability of herbicides/pesticides formulated with surfactants, and the role of surfactants used to accelerate bioremediation of hydrocarbon-polluted soils.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

The role of surface roughness in the wettability and floatability of quartz particles

2020 ◽  
Vol 527 ◽  
pp. 146799 ◽  
Author(s):  
Zhanglei Zhu ◽  
Wanzhong Yin ◽  
Donghui Wang ◽  
Haoran Sun ◽  
Keqiang Chen ◽  
...  
Keyword(s):  
Surface Roughness
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