Influence of surface morphology and nano-structure on hydrophobicity: A molecular dynamics approach

Hosseini, S. J. F.; Savaloni, Hadi; Shahraki, Mehran Gholipour

doi:10.1016/j.apsusc.2019.04.236

Cited by 27 publications

(16 citation statements)

References 52 publications

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“…If the contact line is divided into much smaller lines, viz., the second level of hierarchy, the related contact angle θ 2 r is distinctively different from θ 1 r of the first level of hierarchy as shown in Figure 5c. These phenomena will be kept on until a homogeneous wetting interface achieved when reaching a level n. Consequently, the contact angle either increases or decreases by adding multiple length scales of roughness at all smaller levels depending on the pinned fraction of each level of hierarchy, which is critical for designing surfaces with various adhesion [28][29][30][31][32][33].…”

Section: Cassie-baxter Modelmentioning

confidence: 99%

Wettability on Different Surfaces

Kwok¹

2020

21st Century Surface Science - A Handbook

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Wettability has been explored for 100 years since it is described by Young’s equation in 1805. It is all known that hydrophilicity means contact angle (θ), θ < 90°; hydrophobicity means contact angle (θ), θ > 90°. The utilization of both hydrophilic surfaces and hydrophobic surfaces has also been achieved in both academic and practical perspectives. In order to understand the wettability of a droplet distributed on the textured surfaces, the relevant models are reviewed along with understanding the formation of contact angle and how it is affected by the roughness of the textured surface aiming to obtain the required surface without considering whether the original material is hydrophilic or hydrophobic.

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Section: Cassie-baxter Modelmentioning

confidence: 99%

Wettability on Different Surfaces

Kwok¹

2020

21st Century Surface Science - A Handbook

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“…18 The droplet contact angle, surface morphology, and droplet size remain important for droplet mobility, and molecular dynamic modeling reveals that surface structures similar to gecko feet skin and lotus leaves appear to be more hydrophobic than other textured surfaces. 19 The model and experimental studies are further extended to include droplet motion over hydrophobic surfaces besides interfacial adhesion. In general, the influence of gravitational and interfacial adhesion remains the major contributor to the droplet kinematic properties such as velocity and acceleration.…”

Section: ■ Introductionmentioning

confidence: 99%

“…On the other hand, model studies incorporating molecular dynamics provide useful information for droplet interfacial adhesion over hydrophobic surfaces . The droplet contact angle, surface morphology, and droplet size remain important for droplet mobility, and molecular dynamic modeling reveals that surface structures similar to gecko feet skin and lotus leaves appear to be more hydrophobic than other textured surfaces . The model and experimental studies are further extended to include droplet motion over hydrophobic surfaces besides interfacial adhesion.…”

Section: Introductionmentioning

confidence: 99%

Droplet Rolling Dynamics over a Hydrophobic Surface with a Minute Width Channel

et al. 2021

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Unidirectional and stabilize droplet rolling over hydrophobic surfaces is critical for self-cleaning applications of large areas. Introducing minute size channels on hydrophobic surfaces in the droplet rolling direction can minimize droplet wobbling and enables unidirectional rolling. The droplet rolling behavior over an inclined hydrophobic surface having a minute size channel is investigated. The flow field developed inside the droplet fluid is numerically simulated in a three-dimensional domain pertinent to experimental conditions. Experiments are carried out using a high-speed facility to monitor and evaluate droplet motion over channeled and flat hydrophobic surfaces. The findings revealed that predictions of the droplet translational velocity and those obtained from the experiments are in good agreement. The presence of a minute channel on the hydrophobic surface gives rise to droplet fluid inflection into the minute channel, which in turn modifies the center of mass of the droplet during rolling. This lowers the droplet wobbling height and enables the droplet to roll unidirectionally along the channel length. Enlarging the channel width on the hydrophobic surface increases droplet kinetic energy dissipation while reducing the droplet rolling speed. The complex flow structures formed in the droplet fluid modifies the pressure along the droplet centerline; however, the droplet fluid pressure remains almost the same order as the Laplace pressure in the upper region of a rolling droplet over the channeled hydrophobic surface.

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“…Non-periodic boundary conditions were utilized during the simulation, so that the interaction between atom from the top of PP model and atom at the bottom of substrate layer can be efficiently avoided. The contact angle of polymer droplet on the metal surface was measured by geometric method [ 23 , 30 ], drawing a circle around the droplet and then a tangent line to the solid-liquid interface by using the AutoCAD software (Autodesk Inc., San Francisco, CA, USA). The contact angle of each image is analyzed four times to obtain the mean value and standard deviation of the data.…”

Section: Methodsmentioning

confidence: 99%

Atomistic Investigation on the Wetting Behavior and Interfacial Joining of Polymer-Metal Interface

Zhou

Jiang

et al. 2020

Polymers

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Polymer-metal hybrid structures can reduce the weight of components while ensuring the structural strength, which in turn save cost and subsequently fuel consumption. The interface strength of polymer-metal hybrid structure is mainly determined by the synergistic effects of interfacial interaction and mechanical interlocking. In this study, the wetting behavior of polypropylene (PP) melt on metal surface was studied by molecular dynamics simulation. Atomistic models with smooth surface and nano-column arrays on Al substrate were constructed. Influences of melt temperature, surface roughness and metal material on the wetting behavior and interfacial joining were analyzed. Afterwards the separation process of injection-molded PP-metal hybrid structure was simulated to analyze joining strength. Results show that the initially sphere-like PP model gradually collapses in the wetting simulation. With a higher temperature, it is easier for molecule chains to spread along the surface. For substrate with rough surface, high density is observed at the bottom or on the upper surface of the column. The contact state is transitioning from Wenzel state to Cassie–Baxter state with the decrease of void fraction. The inner force of injection-molded PP-Fe hybrid structure during the separation process is obviously higher, demonstrating a greater joining strength.

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Influence of surface morphology and nano-structure on hydrophobicity: A molecular dynamics approach

Cited by 27 publications

References 52 publications

Wettability on Different Surfaces

Wettability on Different Surfaces

Droplet Rolling Dynamics over a Hydrophobic Surface with a Minute Width Channel

Atomistic Investigation on the Wetting Behavior and Interfacial Joining of Polymer-Metal Interface

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