scholarly journals Fabrication of Anti-Reflective Surface with Superhydrophobicity/High Oleophobicity and Enhanced Mechanical Durability via Nanosecond Laser Surface Texturing

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5691
Author(s):  
Huixin Wang ◽  
Jian Zhuang ◽  
Jiangtao Yu ◽  
Hongyan Qi ◽  
Yunhai Ma ◽  
...  
Keyword(s):  
Abrasion Resistance ◽  
Spectral Reflectance ◽  
Contact Angles ◽  
Experimental Results ◽  
Laser Surface Texturing ◽  
Engine Oil ◽  
Nanosecond Laser ◽  
Reflective Surface ◽  
Mechanical Durability ◽  
Surface Patterns

In this work, anti-reflective surface with superhydrophobicity/oleophobicity and enhanced abrasion resistance was fabricated on steel alloy surface. Two different surface patterns (i.e., parallel microgrooves and spot arrays) were created by nanosecond laser ablation and chemical immersion. The surface micro/nanostructure, spectral reflectance, wettability, and abrasion resistance of all the samples were determined. The experimental results showed that the laser-chemical treated surfaces exhibited much lower spectral reflectance and significantly enhanced surface integrities compared with the untreated surface. Firstly, the contact angles of water, glycerol, and engine oil on the laser-chemical treated surfaces were increased up to 158.9°, 157.2°, and 130.0° respectively, meaning the laser-chemical treated surfaces achieved both superhydrophobicity and high oleophobicity. Secondly, the laser-chemical treated surface showed enhanced abrasion resistance. The experimental results indicated that the spectral reflectance of the laser-chemical treated surfaces remained almost unchanged, while the laser-chemical treated surface patterned with parallel microgrooves sustained superhydrophobicity with a water contact angle of 150.2° even after more than one hundred abrasion cycles, demonstrating the superior mechanical durability. Overall, this fabrication method has shown its effectiveness for fabrication of multifunctional metal surface integrating the surface functionalities of anti-reflectivity, superhydrophobicity/high oleophobicity, and enhanced abrasion resistance.

scholarly journals Nanosecond Laser Fabrication of Hydrophobic Stainless Steel Surfaces: The Impact on Microstructure and Corrosion Resistance

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1577 ◽  
Author(s):  
Mehran Rafieazad ◽  
Jaffer Jaffer ◽  
Cong Cui ◽  
Xili Duan ◽  
Ali Nasiri
Keyword(s):  
Stainless Steel ◽  
Base Metal ◽  
Melting Process ◽  
Contact Angles ◽  
Laser Surface Texturing ◽  
Nanosecond Laser ◽  
Textured Surfaces ◽  
Laser Texturing ◽  
Steel Surfaces ◽  
The Impact

Creation of hydrophobic and superhydrophobic surfaces has attracted broad attention as a promising solution for protection of metal surfaces from corrosive environments. This work investigates the capability of nanosecond fiber laser surface texturing followed by a low energy coating in the fabrication of hydrophobic 17-4 PH stainless steel surfaces as an alternative to the ultrashort lasers previously utilized for hydrophobic surfaces production. Laser texturing of the surface followed by applying the hydrophobic coating resulted in steady-state contact angles of up to 145°, while the non-textured coated base metal exhibited the contact angle of 121°. The microstructure and compositional analysis results confirmed that the laser texturing process neither affects the microstructure of the base metal nor causes elemental loss from the melted regions during the ultrafast melting process. However, the electrochemical measurements demonstrated that the water-repelling property of the surface did not contribute to the anticorrosion capability of the substrate. The resultant higher corrosion current density, lower corrosion potential, and higher corrosion rate of the laser textured surfaces were ascribed to the size of fabricated surface micro-grooves, which cannot retain the entrapped air inside the hierarchical structure when fully immersed in a corrosive medium, thus degrading the material’s corrosion performance.

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.

scholarly journals Testing of yarn abrasion

2013 ◽  
Vol 13 (1) ◽  
pp. 22-27
Author(s):  
G. Krupincová ◽  
J. Hatipoglu
Keyword(s):  
Abrasion Resistance ◽  
Fiber Material ◽  
Experimental Results ◽  
Mechanical Parameters ◽  
Yarn Quality ◽  
Material Characteristics ◽  
Quality Testing

Abstract There exist a lot of methodologies, which can be used for yarn quality testing. Abrasion resistance and its measurement for raw and sized yarn can help in the judgment of yarn weaving-ability. This article concentrates on the possibility of yarn abrasion expression and testing. Relation among fiber material characteristics, selected yarn structural, and mechanical parameters is discussed and a few experimental results are shown.

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.

scholarly journals Creation of Superhydrophobic and Superhydrophilic Surfaces on ABS Employing a Nanosecond Laser

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2547 ◽  
Author(s):  
Cristian Lavieja ◽  
Luis Oriol ◽  
José-Ignacio Peña
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Laser Pulses ◽  
Green Laser ◽  
Contact Angles ◽  
Material Surface ◽  
Nanosecond Laser ◽  
Focal Position ◽  
Superhydrophilic Surface ◽  
Wetting Behaviors ◽  
Superhydrophilic Surfaces

A nanosecond green laser was employed to obtain both superhydrophobic and superhydrophilic surfaces on a white commercial acrylonitrile-butadiene-styrene copolymer (ABS). These wetting behaviors were directly related to a laser-induced superficial modification. A predefined pattern was not produced by the laser, rather, the entire surface was covered with laser pulses at 1200 DPI by placing the sample at different positions along the focal axis. The changes were related to the laser fluence used in each case. The highest fluence, on the focal position, induced a drastic heating of the material surface, and this enabled the melted material to flow, thus leading to an almost flat superhydrophilic surface. By contrast, the use of a lower fluence by placing the sample 0.8 µm out of the focal position led to a poor material flow and a fast cooling that froze in a rugged superhydrophobic surface. Contact angles higher than 150° and roll angles of less than 10° were obtained. These wetting behaviors were stable over time.

New Algorithm for Engine Oil Identification by Infrared Spectrum

2014 ◽  
Vol 1081 ◽  
pp. 353-357
Author(s):  
Yong Gang Shi ◽  
Hao Wen ◽  
Hai Feng Gong ◽  
Zi Cun Li ◽  
Bin Su ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Ir Spectra ◽  
Quality Index ◽  
Experimental Results ◽  
Engine Oil ◽  
Evaluation Index ◽  
Weight Factor ◽  
Engine Oils ◽  
Composition Characteristics

Based on structure and composition characteristics of engine oil, the new algorithm for its Infrared Spectrum (IR) Identification has been put forward. The Hit Quality Index and Related Hit Quality Index are widely used in Infrared Spectrum Identification recently. The two methods don’t take the importance of the variables into consideration and cannot distinguish the unobvious variation in IR spectra. Therefore the diversity weight factor was introduced into the new algorithm to promote its selectivity. The experimental results had shown that the new spectrum similarity evaluation index could distinguish the unobvious spectrum variations and to improve the infrared spectrum identification capability of engine oils.

Thermal Science of Weld Bead Defects: A Review

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
P. S. Wei
Keyword(s):  
Stress Concentration ◽  
Experimental Results ◽  
Materials Processing ◽  
Scale Analysis ◽  
Fluid Physics ◽  
The Past ◽  
Good Comparison ◽  
Surface Patterns ◽  
Pattern Formations ◽  
Working Parameters

Mechanisms for the formation of bead defects, such as humping, gouging, rippling, and other unexpected surface patterns, encountered in welding or drilling are interpreted and reviewed from thermal-fluid science viewpoint. These defects usually accompanying with porosity, undercut, segregation, stress concentration, etc., seriously reduce the properties and strength of the joint or solidification. Even though different mechanisms for formation of the defects have been extensively proposed in the past, more systematical understanding of pattern formations from thermal, fluid, physics, electromagnetic, pattern selections, and metallurgy sciences is still limited. The effects of working parameters and properties on humping and rippling, for example, can be systematically and quantitatively interpreted from scale analysis presented in this work. Good comparison with experimental results reveals mechanisms of different surface patterns. The mechanistic findings for bead defects are also useful for other manufacturing and materials processing.

Improved abrasion resistance of textile fabrics due to polymer coatings

2018 ◽  
Vol 49 (5) ◽  
pp. 572-583
Author(s):  
Martin Wortmann ◽  
Natalie Frese ◽  
Lubos Hes ◽  
Armin Gölzhäuser ◽  
Elmar Moritzer ◽  
...  
Keyword(s):  
Water Vapor ◽  
Abrasion Resistance ◽  
Polymer Coatings ◽  
Contact Angles ◽  
Woven Fabrics ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Slight Reduction ◽  
Textile Fabrics ◽  
Technical Textiles

Textile fabrics are often subject to abrasion, starting from exposed parts of garments to a variety of technical textiles. Abrasion protection by usual coatings, however, can significantly decrease the water vapor transport through a fabric which is often not desired, especially in the case of garments. In our paper, we report on an approach to combine increased abrasion resistance with sufficient water vapor transport properties. For this, different polymers (poly(methyl methacrylate), acrylonitrile butadiene styrene, or amorphous polyamides) were coated on cotton and polyester woven fabrics. The results of abrasion tests against sandpaper show significantly increased abrasion resistance. The absolute evaporation resistance, measured by a Permetest testing device, was only slightly increased up to values still acceptable for typical garments. Images of all coatings by helium ion microscopy deliver an explanation for the measuring results. Polymer coatings on the polyester fabric resulted in a slight reduction of the hydrophobicity, while coating the cotton fabric severely increased the contact angles of the originally superhydrophilic material.

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