Influence of surface roughness on the wetting angle

1995 ◽  
Vol 10 (8) ◽  
pp. 1984-1992 ◽  
Author(s):  
X.B. Zhou ◽  
J.Th.M. De Hosson
Keyword(s):  
Surface Roughness ◽  
Gaussian Distribution ◽  
Rough Surfaces ◽  
Contact Angles ◽  
Wetting Angle ◽  
Experimental Results ◽  
Solid Surfaces ◽  
Roughness Measurements

A this paper the influence of surface roughness on contact angles in the system of liquid Al wetting solid surfaces of Al2O3 has been studied. It was observed that contact angles of liquid Al vary significantly on different rough surfaces of Al2O3. A model is proposed to correlate contact angles with conventional roughness measurements and wavelengths by assuming a cosine profile of rough grooves with a Gaussian distribution of amplitudes. In comparison with the experimental results, the model provides a good estimate for describing the influence of surface roughness on contact angles of liquid Al on Al2O3.

Application of Boltzmann Statistical Mechanics in the Validation of the Gaussian Summit-Height Distribution in Rough Surfaces

1997 ◽  
Vol 119 (4) ◽  
pp. 846-850 ◽  
Author(s):  
M. Leung ◽  
C. K. Hsieh ◽  
D. Y. Goswami
Keyword(s):  
Surface Roughness ◽  
Statistical Mechanics ◽  
Theoretical Basis ◽  
Rough Surfaces ◽  
Electrical Contact ◽  
Height Distribution ◽  
Probable Distribution ◽  
Theoretical Predictions ◽  
Most Probable Distribution ◽  
Roughness Measurements

In theoretical modeling of contact mechanics, a homogeneously, isotropically rough surface is usually assumed to be a flat plane covered with asperities of a Gaussian summit-height distribution. This assumption yields satisfactory results between theoretical predictions and experimental measurements of the physical characteristics, such as thermal/electrical contact conductance and friction coefficient. However, lack of theoretical basis of this assumption motivates further study in surface modeling. This paper presents a theoretical investigation by statistical mechanics to determine surface roughness in terms of the most probable distribution of surface asperities. Based upon the surface roughness measurements as statistical constraints, the Boltzmann statistical model derives a distribution equivalent to Gaussian. The Boltzmann statistical mechanics derivation in this paper provides a rigorous validation of the Gaussian summit-height assumption presently in use for study of rough 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.

scholarly journals Recent Advancements in Fractal Geometric-Based Nonlinear Time Series Solutions to the Micro-Quasistatic Thermoviscoelastic Creep for Rough Surfaces in Contact

2011 ◽  
Vol 2011 ◽  
pp. 1-29 ◽  
Author(s):  
Osama M. Abuzeid ◽  
Anas N. Al-Rabadi ◽  
Hashem S. Alkhaldi
Keyword(s):  
Surface Roughness ◽  
Rough Surfaces ◽  
Power Laws ◽  
Experimental Models ◽  
Experimental Results ◽  
Closed Form Solutions ◽  
In Series ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Surface Creep

To understand the tripological contact phenomena, both mathematical and experimental models are needed. In this work, fractal mathematical models are used to model the experimental results obtained from literature. Fractal geometry, using a deterministic Cantor structure, is used to model the surface topography, where recent advancements in thermoviscoelastic creep contact of rough surfaces are introduced. Various viscoelastic idealizations are used to model the surface materials, for example, Maxwell, Kelvin-Voigt, Standard Linear Solid and Jeffrey media. Such media are modelled as arrangements of elastic springs and viscous dashpots in parallel and/or in series. Asymptotic power laws, through hypergeometric series, were used to express the surface creep as a function of remote forces, body temperatures and time. The introduced models are valid only when the creep approach of the contact surfaces is in the order of the size of the surface roughness. The obtained results using such models, which admit closed-form solutions, are displayed graphically for selected values of the systems' parameters; the fractal surface roughness and various material properties. Results obtained showed good agreement with published experimental results, where the utilized methodology can be further extended to the utilization for the contact of surfaces within micro- and nano-electronic devices, circuits and systems.

The Effect of Substrate Wettability on Hydrazine-Processed CZTS Thin Films

2014 ◽  
Vol 1648 ◽  
Author(s):  
Zhaoning Song ◽  
Adam B. Phillips ◽  
Yao Xie ◽  
Rajendra R. Khanal ◽  
Jon M. Stone ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Soda Lime ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Work Of Adhesion ◽  
Soda Lime Glass ◽  
Single Walled Nanotubes ◽  
Czts Thin Films ◽  
Hydrazine Solution

ABSTRACTWe report a study on the wetting and spreading of hydrazine-CZTS solution on a series of solid surfaces. The work of adhesion between a hydrazine solution and soda-lime glass, Si, graphite, ITO, SnO2, ZnO, CdS, In2S3, Cu, Au, Ag, Al, Ni, Mo, and carbon single-walled nanotubes was calculated using observed contact angles and the areas of the interface. The surface roughness of drop-casted CZTS precursor films was lower on surfaces with better hydrazine wettability. This suggests that the surface roughness of solution-processed films can be controlled by altering the wetting behavior of the solution on the substrate.

scholarly journals Insights into the Multilevel Structural Characterization and Adsorption Mechanism of Sinogastromyzon szechuanensis Sucker on the Rough Surface

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 952
Author(s):  
Qian Cong ◽  
Jin Xu ◽  
Jiaxiang Fan ◽  
Tingkun Chen ◽  
Shaofeng Ru
Keyword(s):  
Surface Roughness ◽  
Spectral Function ◽  
Rough Surface ◽  
Structural Characterization ◽  
Adsorption Mechanism ◽  
Rough Surfaces ◽  
Experimental Results ◽  
Adsorption Performance ◽  
Multilevel Structure ◽  
New Type

The present study investigates the adsorption performance and adsorption mechanism of Sinogastromyzon szechuanensis on different rough surfaces. The different positions of the sucker surface of Sinogastromyzon szechuanensis were observed by adopting the stereomicroscope and SEM. The observed results showed that the sucker of Sinogastromyzonszechuanensis had a multilevel structure of villi and groove. The anterior and posterior of Sinogastromyzonszechuanensis had different microscopic morphologies. The surface roughness of the adsorption substrate ranged from 7 μm to 188 μm. Adsorption strength of Sinogastromyzonszechuanensis and the conventional sucker on different rough surfaces were measured by a purposely designed device. The results showed that the back of Sinogastromyzonszechuanensis mainly provided the adsorption strength. The adsorption strength of the conventional sucker gradually decreased with surface roughness increasing, but the adsorption strength of Sinogastromyzon szechuanensis had not changed significantly. Based on the experimental results, the adsorption mechanism of Sinogastromyzonszechuanensis on the surface with different roughness was analyzed by the spectral function. The Sinogastromyzonszechuanensis sucker with a multilevel structure worked well on the rough surface, which led to Sinogastromyzonszechuanensis with a good sealing on the rough surface. The present work could help to develop a new type of sucker with effective adsorption performance on a rough surface to meet the needs of the engineering field.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

scholarly journals Atomic force microscopy comparative analysis of the surface roughness of two posterior chamber phakic intraocular lens models: ICL versus IPCL

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juan Gros-Otero ◽  
Samira Ketabi ◽  
Rafael Cañones-Zafra ◽  
Montserrat Garcia-Gonzalez ◽  
Cesar Villa-Collar ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Intraocular Lenses ◽  
Posterior Chamber ◽  
Anterior Surface ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Phakic Intraocular Lenses ◽  
Roughness Measurements

Abstract Background To compare the anterior surface roughness of two commercially available posterior chamber phakic intraocular lenses (IOLs) using atomic force microscopy (AFM). Methods Four phakic IOLs were used for this prospective, experimental study: two Visian ICL EVO+ V5 lenses and two iPCL 2.0 lenses. All of them were brand new, were not previously implanted in humans, were monofocal and had a dioptric power of − 12 diopters (D). The anterior surface roughness was assessed using a JPK NanoWizard II® atomic force microscope in contact mode immersed in liquid. Olympus OMCL-RC800PSA commercial silicon nitride cantilever tips were used. Anterior surface roughness measurements were made in 7 areas of 10 × 10 μm at 512 × 512 point resolution. The roughness was measured using the root-mean-square (RMS) value within the given regions. Results The mean of all anterior surface roughness measurements was 6.09 ± 1.33 nm (nm) in the Visian ICL EVO+ V5 and 3.49 ± 0.41 nm in the iPCL 2.0 (p = 0.001). Conclusion In the current study, we found a statistically significant smoother anterior surface in the iPCL 2.0 phakic intraocular lenses compared with the VISIAN ICL EVO+ V5 lenses when studied with atomic force microscopy.

Sign in / Sign up

Export Citation Format

Share Document