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Wetting angle stability of steel surface structures after laser treatment
摘要： In this work, we have used a nanosecond pulsed fiber laser to modify the wettability characteristics of AISI 430 steel. For this, various surface morphologies were created on the samples by laser irradiation with different overlapping and intensity parameters. Immediately upon laser treatment, all the structured samples acquired either hydrophilic or superhydrophilic wetting angles. All the samples were also analyzed with XRD. Then, laser-treated samples were kept in ambient air and/or low-temperature annealing was applied to reach hydrophobic surface properties. Interestingly, these surfaces returned back practically to their initial wetting state by cleaning in an ultrasonic bath. The obtained results are analyzed based on the existing wettability models.
关键词： Nanosecond laser structuring,Hydrophobic and hydrophilic surfaces,Wettability transition,Wetting angle stability
更新于2025-09-19 17:13:59
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Effect of Laser Loop on Surface Morphology of Copper Substrate and Wettability of Solder Joint
摘要： The effect of different laser loop parameter on the geometry of micro-groove pattern on copper substrate and its effect on the wettability was investigated. The micro-grooves pattern was fabricated on the copper surface through laser surface texturing process. 3D measuring laser microscope and contact angle measurement test was conducted to measure the geometry of the micro-grooves pattern and wettability of the solder joint respectively. The results showed that the improvement in laser loop parameter increased the depth of the micro-grooves due to the more exposed time which allows more material ablation. It also showed that the contact angle of textured substrate is smaller than the untextured substrate which results in better wettability.
关键词： wettability,laser loop,copper substrate,solder joint,surface morphology
更新于2025-09-19 17:13:59
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Laser-assisted surface processing for functionalization of polymers on micro- and nano-scale
摘要： Rapid manufacturing of functionalized polymers enable a cost-ef?cient method for many applications in the biological, and medical sector. Laser structuring techniques differ for fast fabrication processes of thermoplastics. Here we report on direct UV laser ablation of polystyrene and polydimethylsiloxane to control wettability and bio-compatibility. For this purpose contact angle measurements and L929 cell growth experiments were performed as function of laser and process parameters. This work also describes the potential of laser-assisted hot embossing which has been introduced to replicate pre-fabricated micro- and nano-sized structures onto polymers proving it to be a cost-ef?cient and ?exible method for surface functionalization. Therefore, pre-fabricated laser-induced periodic surface structures have been manufactured as mould inserts using ultrafast laser radiation near the ablation threshold. These mould inserts can also be made of nickel, silicon or glass proving laser-assisted hot embossing to be a versatile tool for the functionalization of thermoplastics and meet the requirements for modern manufacturing with regard to quality and production ?exibility.
关键词： Bio-compatibility,Functionalization of polymers,Wettability,Laser-assisted surface processing,Laser-assisted hot embossing,Micro- and nano-scale
更新于2025-09-19 17:13:59
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Roughness and wettability properties of plain and silica-coated copper surfaces textured with picosecond laser
摘要： Many recent studies have investigated the mechanism of wettability transition of laser-textured copper surfaces on di?erent materials. Furthermore, several such studies have focused on approaches to accelerate wettability transition from hydrophilicity to hydrophobicity, such as temperature annealing and the use of chemical solutions. However, few researchers have focused on maintaining the initial hydrophilicity of laser-textured surfaces. This study presents a hybrid surface modi?cation method involving chemical bath deposition and ultrafast laser. First, the selected copper substrates are modi?ed using the sol-gel method through dip coating. Subsequently, the coated copper surfaces are irradiated with a picosecond laser. After laser texturing, bumpy structures are formed, and SiO2 nanoparticles can be sintered on the surfaces. Thus, the original hydrophilicity can be maintained, and the surface roughness can be enhanced simultaneously. By using this hybrid modi?cation method, a heterogeneous surface with high-precision patterns can be obtained. Moreover, the mechanism of wettability transition of laser-textured copper surfaces with di?erent laser ?uences is discussed using the Wenzel and Cassie Baxter wetting model by analyzing the chemical composition and surface morphology of the treated surfaces.
关键词： Roughness,Copper,Laser texturing,Wettability,Picosecond laser,Sol-gel
更新于2025-09-19 17:13:59
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Dynamic Multifocus Laser Writing with Acousto‐Optofluidics
摘要： Laser writing of materials is normally performed by the sequential scanning of a single focused beam across a sample. This process is time-consuming and it can severely limit the throughput of laser systems in key applications such as surgery, microelectronics, or manufacturing. A parallelization strategy based on ultrasound waves in a liquid to diffract light into multiple beamlets is reported. Adjusting amplitude, frequency, or phase of ultrasound allows tunable multifocus distributions with sub-microsecond control. When combined with sample translation, the dynamic splitting of light leads to high-throughput laser processing, as demonstrated by locally modifying the morphological and wettability properties of metals, polymers, and ceramics. The results illustrate how acousto-optofluidic systems are universal tools for fast multifocus generation, with potential impact in fields such as imaging or optical trapping.
关键词： complex patterning,laser ablation,high throughput processing,wettability
更新于2025-09-19 17:13:59
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Counterion‐Switched Reversibly Hydrophilic and Hydrophobic TiO <sub/>2</sub> ‐Incorporated Layer‐By‐Layer Self‐Assembled Membrane for Nanofiltration
摘要： The manipulation of surface wettability has been regarded as an efficient strategy to improve the membrane performances. Herein, the counterion-switched reversibly hydrophilic and hydrophobic surface of TiO2-loaded polyelectrolyte membrane are prepared by layer-by-layer assembly of poly(sodium 4-styrene sulfonate) (PSS) and poly(diallydimethyl-ammoniumchloride (PDDA) containing TiO2@PDDA nanoparticles (NPs) on the hydrolyzed polyacrylonitrile (PAN) substrate membrane. The obtained polyelectrolyte multilayer (PEM) membranes [PEM-TiO2]4.5+X? (X? = Cl?, PFO? [perfluorooctanoate] etc.) show different hydrophilicity and hydrophobicity with various counterions. The integration of TiO2 NPs obviously improves the wettability and nanofiltration (NF) performance of PEM membrane for (non)aqueous system of dyes (crystal violet, eriochrome black T) with a high recyclability. The highly hydrophilic [PEM-TiO2]4.5+Cl? (water contact angle [WCA]: 13.2 ± 1.8°) and hydrophobic [PEM-TiO2]4.5+PFO? (WCA: 115.4 ± 2.3°) can be reversibly switched via counterion exchange between Cl? and PFO?, verifying the surface with a reversible hydrophilic–hydrophobic transformation. For such membranes, the morphology, wettability, and NF performance rely on the loading of TiO2@PDDA NPs and surface counterion. Meanwhile, the motion and interaction of water or ethanol in the hydrophilic or hydrophobic membrane are revealed by low-field nuclear magnetic resonance. This work provides a facile and rapid approach to fabricate smart and tunable wetting surface for potential utilization in (non)aqueous NF separation.
关键词： (non)aqueous nanofiltration,TiO2-incoporated polyelectrolyte multilayer membranes,counterion-switched surfaces,LbL self-assembly,reversible wettability
更新于2025-09-19 17:13:59
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Fabrication of controllable wettability of crystalline silicon surfaces by laser surface texturing and silanization
摘要： This paper aims to explore the e?ects of laser surface texturing and chemical modi?cations by silanization on the wettability of silicon surfaces. To e?ectively prepare super-hydrophobic surfaces on silicon, a process using laser texturing with following silanization treatment is used to modify the surface. The surface wettability is evaluated by water contact angle (WCA). To ascertain the e?ect of laser texturing on wettability, the morphological and metallurgical modi?cations of the surface were investigated by scanning electron microscopy (SEM), white light confocal microscope and X-ray photoelectron spectroscopy (XPS). It is found that the fresh laser-processed silicon surface is super-hydrophilic, which is in line with the Wenzel model. A super-hydrophobic surface with a WCA > 150° was successfully obtained after silanization treatment. Silanization by a concentration of 0.72 wt% 1H, 1H, 2H, 2H-per?uorodecyltrichlorosilane with 2 h of immersion time was found to be the most e?ective condition for achieving super-hydrophobic silicon surfaces. The e?ects of acids, alkalis and salts on wettability have also been assessed. The results indicate that as-prepared silicon samples with a ?uoride coating can be normally used in acid condition but not suitable for use in alkaline and salty environments.
关键词： Laser texturing,Wettability,Silanization,Alkalinity,Silicon,Acidity,Salinity
更新于2025-09-16 10:30:52
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Wettability analysis of water on metal/semiconductor phases selectively structured with femtosecond laser-induced periodic surface structures
摘要： Femtosecond (fs) laser-induced periodic surface structures (LIPSS) were selectively generated on the surface of an Ag-Si alloy consisting of a metallic and a semiconducting phase. For this purpose, the alloy was irradiated with linearly polarized fs-laser pulses (τ = 300 fs, λ = 1025 nm, frep = 100 kHz) using a laser peak fluence F = 0.30 J/cm2. Due to the different light absorption behavior of the semiconductor (Si) and the metal (Ag) phase that results in different ablation thresholds of the respective phase, pronounced LIPSS with a period of Λ ≈ 950 nm and a modulation depth of h ≈ 220 nm were generated solely on the Si phase. The alloy surface was characterized by scanning electron microscopy, optical microscopy, white light interference microscopy and atomic force microscopy before and after laser irradiation. Chemical analysis was carried out by energy dispersive X-ray spectroscopy, revealing surface oxidation of the Si phase and no laser-induced chemical modification of the Ag phase. The surface wettability of the alloy was evaluated with distilled water and compared to the single constituents of the composites. After fs-laser irradiation, the surface is characterized by a reduced hydrophilic water contact angle. Furthermore, the alloy selectively structured with LIPSS revealed a droplet shape change due to the distinctly different contact angles on the Si (θ = 5°) and the Ag (θ = 74°) phase. This phenomenon was evaluated and discussed by local contact angle analyses using a confocal laser scanning microscope and a Rhodamine B dye. In addition, it was shown that the shape change due to different contact angles of the components allowed a targeted droplet movement on a macroscopic material boundary (Ag/Si) of the alloy. Selectively structured metal/semiconductor surfaces might be of particular interest for microfluidic devices with a directional droplet movement and for fundamental research of wettability.
关键词： Contact angle,Wettability,Microfluidic devices,LIPSS,Ag-Si alloy,Femtosecond laser
更新于2025-09-12 10:27:22
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Tribological performance of metal-reinforced ceramic composites selectively structured with femtosecond laser-induced periodic surface structures
摘要： The impact of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on tribological properties was investigated for metal-reinforced ceramic composites (Al2O3-ZrO2-Nb). For this purpose, the metallic niobium (Nb) phase was selectively structured with LIPSS in an air environment with different values of the fs-laser peak fluence by near-infrared fs-laser radiation (λ = 1,025 nm, τ = 300 fs, frep = 1 kHz), taking advantage of the different light absorption behavior of ceramic and metal. The tribological performance was evaluated by reciprocating sliding tests in a ball-on-disc configuration using Ringer’s solution as lubricant. The surfaces were characterized before and after laser irradiation by optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and by measuring the contact angle with Ringer’s solution. The LIPSS formation resulted in an increased wetting of the surface with the lubricant. Moreover, the selectively structured composite surfaces revealed a coefficient of friction significantly reduced by a factor of ~ 3 when compared to the non-irradiated surface. Furthermore, the formation of a laser-induced oxidation layer was detected with NbO as the most prominent oxidation state. Selectively structured composites with outstanding mechanical properties and enhanced tribological performance are of particular interest for biomedical applications.
关键词： femtosecond laser-induced periodic surface structures (LIPSS),tribology,wettability,ceramic matrix composites,coefficient of friction,selective surface structuring
更新于2025-09-12 10:27:22
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Modification of ABS wetting properties by ultrashort and short pulse lasers
摘要： Wetting is an important property of solid surfaces, where the surface roughness has a meaningful influence on it. This study focuses on the wetting behavior of micro-textures fabricated on acrylonitrile butadiene styrene (ABS) thermoplastic polymer to provide it anti-fingerprint properties. The structuring process was performed by ultrashort (picosecond) and short (nanosecond) pulses based on square pillars. Wetting behavior was assessed by water and oleic acid static and dynamic (hysteresis) contact angles. Both sort of micro-textures displayed a water contact angle tailored from 90. Apparent color changes induced by laser were assessed to get information about the aesthetical appearance.
关键词： ultrashort pulses,polymers,wettability,short pulses.,laser radiation,contact angle
更新于2025-09-12 10:27:22