Size dependence of bubble wetting on surfaces: breakdown of contact angle match between small sized bubbles and droplets

Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2823-2828 ◽  
Author(s):  
Hongguang Zhang ◽  
Xianren Zhang
Keyword(s):  
Contact Angle ◽  
Size Dependence ◽  
Contact Angles ◽  
Size Dependent ◽  
Angle Match ◽  
Wetting Behaviors ◽  
Small Bubbles

Bubbles show size-dependent wetting behaviors and contact angles for small bubbles are no longer supplementary to those of droplets.

Comment on “Size dependence of bubble wetting on surfaces: breakdown of contact angle match between small sized bubbles and droplets” by H. Zhang and X. Zhang, Nanoscale, 2019, 11, 2823

Nanoscale ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 4308-4310 ◽  
Author(s):  
Anatoly I. Rusanov ◽  
Dmitry V. Tatyanenko ◽  
Alexander K. Shchekin
Keyword(s):  
Contact Angle ◽  
Size Dependence ◽  
Line Tension ◽  
Angle Size ◽  
Simulation Results ◽  
Angle Match

The theoretical arguments of the paper commented contain errors and cannot explain the simulation results. We suggest that line tension and adsorptions at interfaces may be responsible for a difference in the contact angle size dependencies for droplets and bubbles.

Wetting Behaviors of an Underwater Oil Droplet on Structured Surfaces

MRS Advances ◽  
2016 ◽  
Vol 1 (10) ◽  
pp. 667-673 ◽  
Author(s):  
Shuai Chen ◽  
Jiadao Wang ◽  
Darong Chen
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Contact Angles ◽  
Silicon Surfaces ◽  
Water Contact ◽  
Structured Surfaces ◽  
Oil Droplet ◽  
Simulation Results ◽  
Dynamics Simulations ◽  
Wetting Behaviors

ABSTRACTIn this study, the wetting behaviors of an underwater oil droplet on structured surfaces were investigated using molecular dynamics simulations and experiments. The wetting states and contact angles of the underwater oil droplet on different hydrophobic surfaces were simulated. The simulation results showed that there were three kinds of equilibrium states on the pillar surfaces: the Wenzel, cross, and Cassie states. Moreover, the equilibrium state of the underwater oil droplet transformed from a Wenzel to Cassie state when the water contact angle decreased. The contact angle of the underwater oil droplet increased as the water contact angle decreased. Furthermore, the wetting behaviors of the underwater oil droplet on rough polytetrafluoroethylene and silicon surfaces were studied in experiments. The experimental results also indicated that the contact angle of the underwater oil droplet increased as the water contact angle decreased, which corresponded well with the simulation results.

Reply to the ‘Comment on “Size dependence of bubble wetting on surfaces: breakdown of contact angle match between small sized bubbles and droplets”’ by A. I. Rusanov, D. V. Tatyanenko and A. K. Shchekin, Nanoscale, 2020, DOI:10.1039/D0NR00232A

Nanoscale ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 4311-4313
Author(s):  
Hongguang Zhang ◽  
Xianren Zhang
Keyword(s):  
Contact Angle ◽  
Size Dependence ◽  
The Difference ◽  
Angle Match

In this Reply, we clarify the rationale behind our conclusions and point out that in their derivation Rusanov et al. failed to consider the difference between bubbles and droplets.

SIZE-DEPENDENT EFFECTS IN ATOMIC CLUSTERS

2020 ◽  
Author(s):  
A. S. Sharipov ◽  
◽  
B. I. Loukhovitski ◽  
Keyword(s):  
Binding Energy ◽  
Physical Properties ◽  
Size Dependence ◽  
Atomic Clusters ◽  
Energy Collision ◽  
Size Dependent

The size-dependence of different physical properties of atomic clusters (by the example of binding energy, collision diameter, and static isotropic polarizability) is discussed.

scholarly journals Study on contact angles and surface energy of MXene films

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5512-5520
Author(s):  
Hang Zhou ◽  
Fuqiang Wang ◽  
Yuwei Wang ◽  
Changping Li ◽  
Changrui Shi ◽  
...  
Keyword(s):  
Surface Energy ◽  
Contact Angles ◽  
Time Dependent ◽  
Wetting Behaviors

This work sheds light on the process- and time-dependent wetting behaviors and surface energy of MXene films.

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.

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

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 Fabrication of elastic, conductive, wear-resistant superhydrophobic composite material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyed Mehran Mirmohammadi ◽  
Sasha Hoshian ◽  
Ville P. Jokinen ◽  
Sami Franssila
Keyword(s):  
Contact Angle ◽  
Composite Material ◽  
Contact Angles ◽  
Wet Etching ◽  
Sliding Angle ◽  
Electrically Conductive ◽  
Wear Resistant ◽  
Nanoscale Structures ◽  
Mechanical Abrasion ◽  
Mechanical Durability

AbstractA polydimethylsiloxane (PDMS)/Cu superhydrophobic composite material is fabricated by wet etching, electroless plating, and polymer casting. The surface topography of the material emerges from hierarchical micro/nanoscale structures of etched aluminum, which are rigorously copied by plated copper. The resulting material is superhydrophobic (contact angle > 170°, sliding angle < 7° with 7 µL droplets), electrically conductive, elastic and wear resistant. The mechanical durability of both the superhydrophobicity and the metallic conductivity are the key advantages of this material. The material is robust against mechanical abrasion (1000 cycles): the contact angles were only marginally lowered, the sliding angles remained below 10°, and the material retained its superhydrophobicity. The resistivity varied from 0.7 × 10–5 Ωm (virgin) to 5 × 10–5 Ωm (1000 abrasion cycles) and 30 × 10–5 Ωm (3000 abrasion cycles). The material also underwent 10,000 cycles of stretching and bending, which led to only minor changes in superhydrophobicity and the resistivity remained below 90 × 10–5 Ωm.

Sign in / Sign up

Export Citation Format

Share Document