scholarly journals Superhydrophobic Surface Preparation and Wettability Transition of Titanium Alloy with Micro/Nano Hierarchical Texture

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2210 ◽  
Author(s):  
Zhiru Yang ◽  
Chongchong Zhu ◽  
Nan Zheng ◽  
Dezheng Le ◽  
Jianzhong Zhou
Keyword(s):  
Contact Angle ◽  
Titanium Alloy ◽  
Low Temperature ◽  
Superhydrophobic Surface ◽  
Contact Angles ◽  
Surface Wettability ◽  
Hydroxyl Groups ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Low Temperature Annealing

Microstructures are applied to various hydrophobic/hydrophilic surfaces due to the role of adjusting the surface wettability. In this paper, a 1064 nm pulsed picosecond laser was applied to prepare a micro/nano hierarchical structure on the surface of the titanium alloy (Ti-6Al-4V). The microstructures consist of dimple arrays with various diameters, depths, and areal densities. They are obtained by controlling the pulse energy and the number of pulses. The nanostructures are periodic ripples, which are defined as laser-induced periodic surface structure (LIPSS), and the dimensional parameter of LIPSS can be adjusted by changing the laser energy density and scanning speed. The contact angles of various laser textured surfaces were measured. It is found that the contact angle increases with the density of micro-textured surface increases, and the wetting state of textured surfaces conforms to the Cassie model. Some laser processed samples were subjected to low-temperature annealing treatment. It is observed that the low-temperature annealing process can accelerate the surface wettability transition significantly, which is attributed to the change of the hydroxyl groups on the surface. Finally, a superhydrophobic surface with the maximum contact angle of 144.58° is obtained.

scholarly journals Laser Texturing for Superwetting Titanium Alloy and Investigation of Its Erosion Resistance

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1547
Author(s):  
Zhiguo Wang ◽  
Jinpeng Song ◽  
Tianyi Wang ◽  
Huixin Wang ◽  
Qinghua Wang
Keyword(s):  
Contact Angle ◽  
Superhydrophobic Surface ◽  
Erosion Resistance ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Ti Alloy ◽  
Textured Surfaces ◽  
Superhydrophilic Surface

Erosion of materials is one of the major causes that lead to the malfunction of equipment and facilities, and surface texturing can be a solution for enhancement of erosion resistance. In this work, superwetting (superhydrophilic/superhydrophobic) titanium (Ti) alloy surface with periodic microstructure was prepared by a facile laser-based surface texturing approach which combines laser surface texturing and low-temperature annealing. The effect of laser-induced surface texture and wettability on the erosion resistance of the laser textured surface was studied. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to analyze the chemical surface microstructure and surface on the untreated and laser textured surfaces. The hardness and contact angle of the untreated surface, superhydrophilic surface and superhydrophobic surface were measured by microhardness tester and contact angle goniometer. Using an in-house built erosion experimental setup, the erosion resistance of the untreated surface, superhydrophilic surface and superhydrophobic surface was investigated. The experimental results demonstrate that micro-bumps are formed after laser surface texturing. In the meantime, the surface hardness for the laser textured surface with a step size of 150 μm is increased by 48% under the load of 1.961 N. Compared with the untreated surface, the erosion resistance is increased by 33.9%, 23.8% and 16.1%, respectively, for the superhydrophobic surface. The SEM results show that the untreated surface has large and deep impact pits, while the superhydrophobic surface only has small and shallow impact pits, indicating that the erosion process resulted in less damage to the substrate. The EDS results shows that superhydrophobicity plays a critical role in protecting the substrate from erosion. It is thus believed that the superhydrophobic surface has pronounced effects for improving the hardness and erosion resistance of Ti alloy.

scholarly journals Blood Platelet’s Behavior on Nanostructured Superhydrophobic Surface

2008 ◽  
Vol 2 ◽  
pp. 129-136 ◽  
Author(s):  
Ming Zhou ◽  
Jia Hong Yang ◽  
Xia Ye ◽  
Ao Ran Zheng ◽  
Gang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Superhydrophobic Surface ◽  
Platelet Adhesion ◽  
Blood Compatibility ◽  
Blood Platelet ◽  
Contact Angles ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Scanning Electron

Regular arrays of micro-pillars and nano-grooves structures on the silicon wafer are fabricated by using soft lithography, and the three dimension morphology of textured surface is observed by using scanning electron microscopy (SEM) and atomic force microscope (AFM). The static water contact angles are measured by using contact angle meter to characterize the wettabilities of these surfaces. To investigate how the presence of topography and the variations of wettability affect the haemocompatibility of textured surface contacted with blood, different patterned surfaces are designed and fabricated, and blood platelet adhesion test is carried out on these surfaces. The adhesion and coagulation of platelets are inspected by scanning electron microscopy (SEM). Experimental data presented in this paper indicate that different surface roughness and wettability are the important factors for blood platelet adhesion. The amount of adsorbed blood platelet is low on textured surfaces, compared with that on the flat surface. Especially, there is no coagulation and activation on the surface with nanometer grooves. That is to say, the superhydrophobic surface is apt to decrease blood platelet adhesion. The study suggests that surface with suitable wettabililty and textured structures exhibits superior blood compatibility.

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 Image Analysis Determination of the Influence of Surface Structure of Silicone Rubbers on Biofouling

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sevil Atarijabarzadeh ◽  
Fritjof Nilsson ◽  
Henrik Hillborg ◽  
Sigbritt Karlsson ◽  
Emma Strömberg
Keyword(s):  
Image Analysis ◽  
Silicone Rubber ◽  
Microbial Growth ◽  
Plane Surface ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Homogeneous Distribution ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Band Formation

This study focuses on how the texture of the silicone rubber material affects the distribution of microbial growth on the surface of materials used for high voltage insulation. The analysis of surface wetting properties showed that the textured surfaces provide higher receding contact angles and therefore lower contact angle hysteresis. The textured surfaces decrease the risk for dry band formation and thus preserve the electrical properties of the material due to a more homogeneous distribution of water on the surface, which, however, promotes the formation of more extensive biofilms. The samples were inoculated with fungal suspension and incubated in a microenvironment chamber simulating authentic conditions in the field. The extent and distribution of microbial growth on the textured and plane surface samples representing the different parts of the insulator housing that is shank and shed were determined by visual inspection and image analysis methods. The results showed that the microbial growth was evenly distributed on the surface of the textured samples but restricted to limited areas on the plane samples. More intensive microbial growth was determined on the textured samples representing sheds. It would therefore be preferable to use the textured surface silicone rubber for the shank of the insulator.

scholarly journals Molecular Dynamics Simulation of Wetting Behavior: Contact Angle Dependency on Water Potential Models

2021 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Lukman Hakim ◽  
Irsandi Dwi Oka Kurniawan ◽  
Ellya Indahyanti ◽  
Irwansyah Putra Pradana
Keyword(s):  
Molecular Dynamics ◽  
Contact Angle ◽  
Liquid Droplet ◽  
Center Of Mass ◽  
Contact Angles ◽  
Surface Wettability ◽  
Dynamics Simulation ◽  
Potential Models ◽  
Surface Hydrophilicity ◽  
Dynamics Simulations

The underlying principle of surface wettability has obtained great attentions for the development of novel functional surfaces. Molecular dynamics simulations has been widely utilized to obtain molecular-level details of surface wettability that is commonly quantified in term of contact angle of a liquid droplet on the surface. In this work, the sensitivity of contact angle calculation at various degrees of surface hydrophilicity to the adopted potential models of water: SPC/E, TIP4P, and TIP5P, is investigated. The simulation cell consists of a water droplet on a structureless surface whose hydrophilicity is modified by introducing a scaling factor to the water-surface interaction parameter. The simulation shows that the differences in contact angle described by the potential models are systematic and become more visible with the increase of the surface hydrophilicity. An alternative method to compute a contact angle based on the height of center-of-mass of the droplet is also evaluated, and the resulting contact angles are generally larger than those determined from the liquid-gas interfacial line.

scholarly journals Wettability on Different Surfaces

2020 ◽  
Author(s):  
Yeeli Kelvii Kwok
Keyword(s):  
Contact Angle ◽  
Textured Surface ◽  
Original Material ◽  
Textured Surfaces ◽  
Hydrophobic Surfaces ◽  
Hydrophilic Surfaces ◽  
Young's Equation

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.

The Effect of Surface Wettability on Viscous Film Deposition

2009 ◽  
Author(s):  
Alexandru Herescu ◽  
Jeffrey S. Allen
Keyword(s):  
Contact Angle ◽  
Film Thickness ◽  
Capillary Number ◽  
High Speed ◽  
Glass Tube ◽  
Contact Angles ◽  
Film Deposition ◽  
Surface Wettability ◽  
Working Fluid ◽  
Uniqueness Of The Solution

The viscous deposition of a liquid film on the inside of a capillary has been experimentally investigated with a focus on the relationship between the film thickness and surface wettability. With distilled water as a working fluid tests were run in a 622 microns diameter glass tube with contact angles of 30° and 105°, respectively. In the first set of experiments the tube was uncoated while in the second set a fluoropolymer coating was applied to increase the contact angle. A film thickness dependence with the contact angle θ (surface wettability) as well as the Capillary number in the form hR ∼ Ca2/3/cosθ is inferred from scaling arguments. For partial wetting it may explain the existence of a thicker film for nonzero contact angle. It was further found that the non-wetting case of 105° contact angle deviates significantly from the existing theories, the film thickness presenting a weak dependence with the Capillary number. This deviation as well as the apparent non-uniqueness of the solution is thought to be caused by the film instability (rupture) observed during the tests. The thickness of the deposited film as a function of the Capillary number was estimated from the liquid mass exiting the capillary and the gas-liquid interface (meniscus) velocity, and compared to Bretherton’s data and a correlation proposed by Quere. The film thickness measurements as well as the meniscus velocity were determined with the aid of a Photron high speed camera with 10000 frames per second sampling capability coupled with a Nikon TE-2000 inverted microscope and a Precisa electronic balance.

Contact Angle of Water Droplets in a High-Temperature, High-Pressure Environment

2004 ◽  
Author(s):  
Tsukasa Hayashi ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Kenrou Takamori
Keyword(s):  
Contact Angle ◽  
High Pressure ◽  
High Temperature ◽  
Contact Angles ◽  
Surface Wettability ◽  
Water Droplets ◽  
Straight Line ◽  
Angle Condition ◽  
High Pressure Environment ◽  
High Temperature High Pressure

This paper presents an experimental study of surface wettability on a stainless plate in a high-temperature, high-pressure environment. Using a pressure vessel, we measured contact angles of water droplets at temperatures from 20 to 300°C and a constant pressure of 15 MPa, as an indicator of macroscopic surface wettability. Measured contact angles decreased with temperature below 250°C, clustering around a straight line at temperatures below 120°C and around another line in the range from 120 to 250°C. At temperatures above 250°C, on the other hand, the contact angles remained constant, independent of temperature, and contrary to the existing theoretical model, no highly hydrophilic condition or null contact angle condition was achieved.

Lattice Boltzmann simulation of immiscible displacement in the cavity with different channel configurations

2017 ◽  
Vol 28 (11) ◽  
pp. 1750136 ◽  
Author(s):  
Qin Lou ◽  
Chenqiang Zang ◽  
Mo Yang ◽  
Hongtao Xu
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Lattice Boltzmann ◽  
Contact Angles ◽  
Surface Wettability ◽  
Immiscible Displacement ◽  
Displacement Efficiency ◽  
Small Contact Angle ◽  
Gas Cavity ◽  
Pseudo Potential

In this work, the immiscible displacement in a cavity with different channel configurations is studied using an improved pseudo-potential lattice Boltzmann equation (LBE) model. This model overcomes the drawback of the dependence of the fluid properties on the grid size, which exists in the original pseudo-potential LBE model. The approach is first validated by the Laplace law. Then, it is employed to study the immiscible displacement process. The influences of different factors, such as the surface wettability, the distance between the gas cavity and liquid cavity and the surface roughness of the channel are investigated. Numerical results show that the displacement efficiency increases and the displacement time decreases with the increase of the surface contact angle. On the other hand, the displacement efficiency increases with increasing distance between the gas cavity and the liquid cavity at first and finally reaches a constant value. As for the surface roughness, two structures (a semicircular cavity and a semicircular bulge) are studied. The comprehensive results show that although the displacement processes for both the structures depend on the surface wettability, they present quite different behaviors. Specially, for the roughness structure constituted by the semicircular cavity, the displacement efficiency decreases and displacement time increases evidently with the size of the semicircular cavity for the small contact angle. The trend slows down as the increase of the contact angle. Once the contact angle exceeds a certain value, the size of the semicircular cavity almost has no influence on the displacement process. While for the roughness structure of a semicircular bulge, the displacement efficiency increases with the size of bulge first and then it decreases for the small contact angle. The displacement efficiency increases first and finally reaches a constant for the large contact angle. The results also show that the displacement time has an extreme value in these cases for the small contact angles.

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