scholarly journals Influence of laser power in nanosecond laser texturing for a hydrophobic state on SS316L

2021 ◽  
Vol 15 (4) ◽  
pp. 8592-8600
Author(s):  
M.H. Zul ◽  
Mahadzir Ishak@Muhammad ◽  
M. H. Aiman ◽  
M. M. Quazi
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Laser Power ◽  
Surface Engineering ◽  
Hydrophobic Surface ◽  
Morphological Properties ◽  
Nanosecond Laser ◽  
Time Interval ◽  
Beam Diameter ◽  
Laser Texturing

The use of lasers in surface engineering has recently made significant progress. The hydrophobic surface is commonly studied because of the application in various fields, including vehicles, aerospace, biomedicine, etc. Since these laser methods require many combination parameters, such as laser power (P), frequency (ƒ), scan speed (ʋ) and laser beam diameter (D), the effect of the parameters must therefore be investigated to produce the hydrophobic condition. This research tries to relate the laser power with the morphological properties and contact angle of the SS316L surfaces. Samples are subjected to laser texturing with different laser power settings. The surface is then characterised by surface roughness, and the contact angle is measured according to a specific time interval. The laser power output and energy density function on the surface and contact angle were investigated in these contexts experimentally. Surface roughness was defined and validated to show that the laser parameters' effect is effective and controllable. This study shows that the laser output intensity significantly contributes to regulating surface roughness and the substrate's wetting activity. The 18W and 24W laser outputs produce a spiked surface with various peaks that cause the surface to become hydrophobic over time because of the air-trap that happens in the valley.

scholarly journals Long-Term Influence of Laser-Processing Parameters on (Super)hydrophobicity Development and Stability of Stainless-Steel Surfaces

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2240 ◽  
Author(s):  
Peter Gregorčič ◽  
Marjetka Conradi ◽  
Luka Hribar ◽  
Matej Hočevar
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Processing Parameters ◽  
Nanosecond Laser ◽  
Stainless Steel Surface ◽  
Textured Surfaces ◽  
Laser Texturing ◽  
Important Challenge ◽  
Faster Development

Controlling the surface wettability represents an important challenge in the field of surface functionalization. Here, the wettability of a stainless-steel surface is modified by 30-ns pulses of a Nd:YAG marking laser (λ = 1064 nm) with peak fluences within the range 3.3–25.1 J cm−2. The short- (40 days), intermediate- (100 days) and long-term (1 year) superhydrophilic-to-(super)hydrophobic transition of the laser-textured surfaces exposed to the atmospheric air is examined by evaluating its wettability in the context of the following parameters: (i) pulse fluence; (ii) scan line separation; (iii) focal position and (iv) wetting period due to contact angle measurements. The results show that using solely a short-term evaluation can lead to wrong conclusions and that the faster development of the hydrophobicity immediately after laser texturing usually leads to lower final contact angle and vice versa, the slower this transition is, the more superhydrophobic the surface is expected to become (possibly even with self-cleaning ability). Depending on laser fluence, the laser-textured surfaces can develop stable or unstable hydrophobicity. Stable hydrophobicity is achieved, if the threshold fluence of 12 J cm−2 is exceeded. We show that by nanosecond-laser texturing a lotus-leaf-like surface with a contact angle above 150° and roll-off angle below 5° can be achieved.

Analysis of Roughness and Heat Affected Zone of Steel Plates Obtained by Laser Cutting

2014 ◽  
Vol 974 ◽  
pp. 169-173 ◽  
Author(s):  
Imed Miraoui ◽  
Mohamed Boujelbene ◽  
Emin Bayraktar
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Heat Affected Zone ◽  
Laser Power ◽  
Laser Cutting ◽  
Major Effect ◽  
Steel Plates ◽  
Beam Diameter ◽  
Laser Beam Diameter ◽  
Cut Surface

In the present study, high-power CO2 laser cutting of steel plates has been investigated and the effect of the input laser cutting parameters on the cut surface quality is analyzed. The average roughness of the cut surface of the specimens, produced by different laser beam diameter and laser power, were measured by using roughness tester. The scanning electron microscopy SEM is used to record possible metallurgical alterations on the cut edge. The aim of this work is to investigate the effect of laser beam diameter and laser power on the cut surface roughness and on the heat affected zone width HAZ of steel plates obtained by CO2 laser cutting. An overall optimization was applied to find out the optimal cutting setting that would improve the cut surface quality. It was found that laser beam diameter has a negligible effect on surface roughness but laser power had major effect on roughness. The cut surface roughness decreases as laser power increases. Improved surface roughness can be obtained at higher laser power. Also, laser beam diameter and laser power had major effect on HAZ width. It increases as laser power increases.

scholarly journals Modification of the copper wettability by nanosecond laser texturing

2021 ◽  
Vol 2119 (1) ◽  
pp. 012126
Author(s):  
M M Vasilev ◽  
Y G Shukhov ◽  
A A Rodionov ◽  
Y P Li ◽  
M K Lei
Keyword(s):  
Contact Angle ◽  
Laser Treatment ◽  
Environmental Exposure ◽  
Nanosecond Laser ◽  
Laser Texturing ◽  
Copper Surfaces ◽  
Over Time

Abstract Nanosecond laser microstructuring of copper surfaces was performed in this work. The contact angle value immediately after laser treatment decreased sharply and all samples were hydrophilic or superhydrophilic. Hydrophobization of the textured samples occurs as a result of environmental exposure over time. Oxidation and adsorption of carbon and its compounds from the atmosphere leads to a change in the wettability of the irradiated surfaces. The acceleration of hydrophobization process with decrease of fluence was found. It is shown that the stable contact angle, reached after one month, does not depend on the value of the fluence and is about 140°.

Roughness Effects on Continuous and Discrete Flows in Superhydrophobic Microchannels

2011 ◽  
Vol 9 (5) ◽  
pp. 1094-1105 ◽  
Author(s):  
Junfeng Zhang ◽  
Daniel Y. Kwok
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Slip Length ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Lattice Boltzmann Model ◽  
Roughness Effects ◽  
Apparent Slip ◽  
Velocity Changes

AbstractThe dynamic behaviors of continuous and discrete flows in superhydrophobic microchannels are investigated with a lattice Boltzmann model. Typical characters of the superhydrophobic phenomenon are well observed from our simulations, including air trapped in the surface microstructures, high contact angles, low contact angle hysteresis, and reduced friction to fluid motions. Increasing the roughness of a hydrophobic surface can produce a large flow rate through the channel due to the trapped air, implying less friction or large apparent slip. The apparent slip length appears to be independent to the channel width and could be considered as a surface property. For a moving droplet, its behavior is affected by the surface roughness from two aspects: the contact angle difference between its two ends and the surface-liquid interfacial friction. As a consequence, the resulting droplet velocity changes with the surface roughness as firstly decreasing and then increasing. Simulation results are also compared with experimental observations and better agreement has been obtained than that from other numerical method. The information from this study could be valuable for microfluidic systems.

EFFECT OF UV RADIATION DURATION AND MOLECULAR WEIGHT TO HYDROPHOBICITY AND SURFACE ROUGHNESS OF POLYSTYRENE COATING ON QCM SENSOR

2017 ◽  
Vol 79 (3) ◽  
Author(s):  
Setyawan P. Sakti ◽  
Layli Amaliya ◽  
Nike F. Khusnah ◽  
Masruroh Masruroh
Keyword(s):  
Molecular Weight ◽  
Surface Roughness ◽  
Contact Angle ◽  
Uv Radiation ◽  
Uv Light ◽  
Hydrophobic Surface ◽  
Surface Radiation ◽  
Coating Materials ◽  
Optical Profilometer ◽  
Uv Lamp

Hydrophobicity is one of important solid surface properties for the development of Quartz Crystal Microbalance (QCM) biosensor. Hydrophobicity plays a role in the biomolecule immobilisation. Polystyrene is one of the coating materials used in the QCM biosensor, where the sensitive biomolecule material is immobilised. Hydrophobicity and surface roughness can be controlled by many methods. In this work, we investigated the effect of the polymer molecular weight and UV radiation on the surface roughness and hydrophobicity. The polystyrene with a molecular weight of 35,000 g/mol, 192,000 g/mol, and 280.000 g/mol were solved in toluene with a concentration of 3%, 5%, and 7% and coated using spin coating method on top of the QCM sensor. The coated polystyrene on QCM sensor was irradiated using UV lamp with a wavelength of 254 nm. The contact angle of water before and after UV irradiated was measured using contact angle instrument and the surface roughness is measured using non-contact optical profilometer. The result shows that the higher molecular weight of polystyrene led to more hydrophobic surface. Radiation under UV light increases the hydrophobicity of polystyrene surface. The surface roughness of the polystyrene on top of the sensor is not affected by UV irradiation. 

scholarly journals THE INFLUENCE OF SILICA CALCINATION TEMPERATURE VARIATION TO THE HYDROPHOBICITY AND TRANSMITTANCE ON GLASS SUBSTRATE

2020 ◽  
Vol 12 (2) ◽  
pp. 49-56
Author(s):  
Roihatur Rohmah ◽  
Mochamad Zainuri
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Calcination Temperature ◽  
Water Contact Angle ◽  
Hydrophobic Surface ◽  
Dip Coating ◽  
Water Contact ◽  
Coating Method ◽  
Composite Filler ◽  
Dip Coating Method

The hydrophobic surface can be self-cleaning. The hierarchy of surface roughness affects the hydrophobic surface. In this research, the hydrophobic surface was fabricated by modification of surface roughness from the composite filler. Natural silica was used as a filler and was done a variation of calcination temperature to modify the hierarchy of roughness formed. The variation of calcination temperature was 800°C, 1000°C, 1200°C, and 1400°C. The coating method was a dip-coating method by 30-second long immersion. A glass as coating media was coated by PVDF/SiO2 composite. The hydrophobic surface could be known from the value of the water contact angle (WCA) formed. If a water contact angle more than 90°, the surface could be called the hydrophobic surface. In this research, the hydrophobicity aspect cause of variation of calcination temperature was known from the value of water contact angle formed on the surface of PVDF/SiO2 composite coating 800°C, 1000°C, 1200°C, and 1400°C was 117,12° ± 0,98°, 107,80° ± 0,91°, 121,31° ± 1,45°, and 111,75° ± 1,47°, respectively.

scholarly journals Polylactic acid scaffolds obtained by 3D printing and modified by oxygen plasma

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Hernane Silva Barud ◽  
Lorenzo Gouvêa Machado ◽  
Mayté Paredes Zaldivar ◽  
Mônica Rosas da Costa Iemma ◽  
Sandra Andrea Cruz ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Surface Roughness ◽  
Contact Angle ◽  
3D Printing ◽  
Cell Viability ◽  
Polylactic Acid ◽  
Oxygen Plasma ◽  
Hydrophobic Surface ◽  
Surface Modifications ◽  
Thermoplastic Polymer

The purpose of tissue engineering is to repair, replace, and regenerate tissues and organs. For this aim, materials supports, as polylactic acid (PLA) are used. PLA is a thermoplastic polymer that presents biodegradability, biocompatibility and good processability. PLA scaffolds can accurately constructed by 3D printing. Then, the objectives of this work were to modify the hydrophobic surface of PLA scaffolds using oxygen plasma and to study the cell viability and proliferation. The characterization was done by AFM, contact angle, FTIR and studies of proliferation and cell viability. Results showed that the material acquired hydrophilic properties by the presence of oxygen reactive species and by contact angle decrease. It was also observed an increase in the surface roughness. We can conclude that although the surface modifications were effective and the PLA scaffolds were not cytotoxic, there were no improvements in the proliferation process with the studied osteo-1 lineage cells. 

scholarly journals Investigation of Multiparameter Laser Stripping of AlTiN and DLC C Coatings

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 951
Author(s):  
Tomáš Primus ◽  
Josef Hlavinka ◽  
Pavel Zeman ◽  
Jan Brajer ◽  
Martin Šorm ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Efficiency ◽  
Steel Substrate ◽  
Cutting Tools ◽  
High Hardness ◽  
Working Time ◽  
Nanosecond Laser ◽  
Altin Coating ◽  
Successful Removal ◽  
Frequency Laser

The lifetime and properties of cutting tools and forming moulds can be prolonged and enhanced by the deposition of hard, thin coatings. After a certain period of usage, the coating will deteriorate. Any remaining coating must be removed prior to successful recoating. Laser stripping is a fast and environmentally friendly coating removal method. In this paper, we present laser removal of two types of coatings deposited on a 1.2379 tool steel substrate, namely, an AlTiN coating with high hardness and a DLC C coating with a small coefficient of friction (COF). A powerful nanosecond laser was employed to remove the coating from the substrate with high efficiency, along with suitable residual surface roughness. Measurements were taken of surface roughness, removed depth, and working time on a stripped area of 1 cm2. The samples were evaluated under a microscope, with a 3D profilometer, and by EDS chemical analysis. Successful removal of the coating was confirmed by optical analysis, but detailed chemical characterisation showed that about 30% of the coating element may remain on the surface. Moreover, a working time of less than 7.5 s per cm2 was obtained in this study. In addition, it was shown that the application of a second low energy, high frequency laser beam pass leads to remelting of the peaks of the material and reduced surface roughness.

scholarly journals Superhydrophobic functionalized cellulosic paper by copper hydroxide nanorods for oils purification

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmed S. Belal ◽  
Jehan El Nady ◽  
Azza Shokry ◽  
Shaker Ebrahim ◽  
Moataz Soliman ◽  
...  
Keyword(s):  
Contact Angle ◽  
Filter Paper ◽  
Separation Efficiency ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Absorption Capacity ◽  
Morphological Properties ◽  
Copper Hydroxide ◽  
Immersion Method ◽  
Water Contact

AbstractOily water contamination has been sighted as one of the most global environmental pollution. Herein, copper hydroxide nanorods layer was constructed onto cellulosic filter paper surface cured with polydopamine, Ag nanoparticles, and Cu NPs through immersion method. This work has been aimed to produce a superhydrophobic and superoleophilic cellulosic filter paper. The structure, crystalline, and morphological properties of these modified cellulosic filter paper were investigated. Scanning electron microscope images confirmed that the modified surface was rougher compared with the pristine surface. The contact angle measurement confirmed the hydrophobic nature of these modified surfaces with a water contact angle of 169.7°. The absorption capacity was 8.2 g/g for diesel oil and the separation efficiency was higher than 99%. It was noted that the flux in the case of low viscosity solvent as n-hexane was 9663.5 Lm−2 h−1, while for the viscous oil as diesel was 1452.7 Lm−2 h−1.

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