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Novel laser textured surface designs for improved zirconia implants performance
摘要： The development of new surface designs to enhance the integration process between surgically placed implants and biological tissues remains a challenge for the scientific community. In this way and trying to overcome this issue, in this work, laser technology was explored to produce novel textures on the surface of green zirconia compacts produced by cold pressing technique. Two strategies regarding line design (8 and 16 lines design) and different laser parameters (laser power and number of laser passages) were explored to assess their influence on geometry and depth of created textures. The produced textures were evaluated with Scanning Electron Microscopy (SEM) and it was observed that well-defined textured surfaces with regular geometric features (cavities or pillars) were obtained by laser combining different strategies lines design and parameters. The potential of proposed textures was also evaluated regarding surface wettability, friction performance (static and dynamic coefficient of friction evolution) against bone, aging resistance and flexural strength. Results demonstrated that all the produced textures display a super hydrophilic or hydrophilic behavior. Regarding the friction behavior, it was experimentally observed a high initial static coefficient of friction (COF) for all produced textures. Concerning the aging resistance, all the textured surfaces revealed a low monoclinic content, less than 25% after 5?h of hydrothermal aging. The flexural strength results showed that the mechanical resistance of zirconia was not significantly compromised with the laser action. Based on the obtained results, it is possible to prove that the processing route used for manufacturing the new and different surface designs (cold pressing technique followed by laser texturing) showed to be particularly effective for the production of zirconia implants with customized surface designs according to the properties required in a specific application. These new surface designs besides to enhance the surface wettability and also to improve the fixation at the initial moment of the implantation, do not significantly compromise the resistance to aging and the mechanical performance of zirconia. Hence, a positive impact on the long-term performance of the zirconia implants may be expected with the proposed novel laser textured surface designs.
关键词： Flexural strength,Aging resistance,Zirconia,Surface wettability,Coefficient of friction,Laser surface texturing
更新于2025-09-12 10:27:22
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[Laser Institute of America ICALEO? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16–20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Controlling the wettability of stainless steel by surface texturing using a high power femtosecond fiber laser
摘要： In this work, stainless steel samples have been textured by a simple and fast one-step laser process. The particularity of this process is the use of an ultrashort pulsed laser technology, combining a high power pulses at high repetition rate. An improved productivity can thus be considered. Successive ablations by IR laser pulses allow to generate dual-scale surface structures. Hierarchical structures, composed of micro-hills on which are superimposed periodic nano-ripples, have been produced at the repetition rate of 50 kHz, by a repeated irradiation of a crossed pattern of parallel lines. In order to increase the process throughput, repetition rates of 100, 250 and 500 kHz have been tested. After an adaptation of the process parameters, topographies with the same dimensions of structures have been created. The presence of these structures modifies the wetting properties of the material. Immediately after laser irradiation the surface becomes hydrophilic; however this wetting state evolves to become superhydrophobic with contact angles higher than 160° and water droplets unable to adhere to the surface. The temporal evolution of the wettability results from the combination of the surface roughness and the chemical composition of this surface. The modeling of the wetting behavior of water droplet, deposited on grooves structures, shows the enhancement of the initial wettability of the surface.
关键词： wettability,superhydrophobic,femtosecond laser,stainless steel,surface texturing
更新于2025-09-12 10:27:22
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Controllable fabrication of unidirectional liquid spreading surface through confining plasma eruption and femtosecond laser double pulses
摘要： The e?cient and simple fabrication of a self-driven, continuous, and controllable unidirectional liquid spreading surface is an enormous challenge. In this paper, we present a maskless, one-step, and controllable method to fabricate unidirectional high-speed liquid spreading surfaces. The method con?nes the eruption of plasma by using oblique glass and femtosecond (fs) laser double pulses. The oblique glass is used to regulate plasma density via plasma con?nement, and the double-pulse is used to control the ?nal processing energy by changing pulse delay. The gradient structure size can be controlled by adjusting the laser energy, pulse delay and the tilted glass angle. Moreover, It has even can both achieved a high-speed and unidirectional spreading. A 1 μL droplet ?ows approximately 7 mm in 640 ms with no increase of the corresponding width using the gradient grating structure fabricated under double pulses with a pulse delay of 1 ps. Using di?erent gradient channel assembly, a selective ?ow along designed direction can be achieved. The selective ?ow phenomenon is observed through customized liquid diode. By manufacturing continuous and adjustable gradient structure, the method is potential to control liquid ?ow in microsystem.
关键词： Wettability gradient surface,Liquid diode,Plasma con?nement,Unidirectional liquid,Double pulse,Femtosecond laser
更新于2025-09-12 10:27:22
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Femtosecond Laser Fabrication of Stable Hydrophilic and Anti-Corrosive Steel Surfaces
摘要： We report on a novel single-step method to develop steel surfaces with permanent highly hydrophilic and anti-corrosive properties, without employing any chemical coating. It is based on the femtosecond (fs) laser processing in a saturated background gas atmosphere. It is particularly shown that the fs laser microstructuring of steel in the presence of ammonia gas gives rise to pseudoperiodic arrays of microcones exhibiting highly hydrophilic properties, which are stable over time. This is in contrast to the conventional fs laser processing of steel in air, which always provides surfaces with progressively increasing hydrophobicity following irradiation. More importantly, the surfaces subjected to fs laser treatment in ammonia exhibit remarkable anti-corrosion properties, contrary to those processed in air, as well as untreated ones. The combination of two functionalities, namely hydrophilicity and corrosion resistance, together with the facile processing performed directly onto the steel surface, without the need to deposit any coating, opens the way for the laser-based production of high-performance steel components for a variety of applications, including mechanical parts, ?uidic components and consumer products.
关键词： femtosecond laser processing,wettability,steel,anticorrosion
更新于2025-09-11 14:15:04
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The homogeneity of multi-textured micro-pattern arrays in a laser shock surface patterning process and its effect on the surface properties of aluminum alloy
摘要： In this study, a laser shock surface patterning process was performed to e?ectively implement hundreds of micro-patterns on a metallic surface through a single laser beam irradiation. Micro-pattern arrays of rectangular, hexagonal, circular, and mesh shapes of various sizes were successfully transferred to the workpiece, and a multi-textured surface structure was realized. In order to improve the homogeneity of the micro-pattern array, it was most e?ective to increase the thickness of the ablation layer. In the case of the thicker ablation layer, it seems that more uniform pressure was transferred to the material because the ablation layer was in a relatively rigid state due to the reduced level of self-deformation. Since the laser shock surface patterning process exerts a strong shock loading along with plastic deformation on the material surface, the hardness value increased mainly around the area subjected to the shock load. The better the homogeneity of the micro-pattern array, the less the deviation in the hardness value. Therefore, it is important to ensure micro-pattern uniformity in order to achieve uniform surface properties. Changes in the contact angle were also observed under various process conditions. After surface patterning, the contact angle increased as the amount of air trapped in the bar region increased. As the laser intensity increased, it was observed that the geometric surface changes were sharp, and the surface structure changed. As a result, the contact between the air and the water droplets decreased, and the contact angle decreased.
关键词： Laser surface pattering,Multi-textured surface,Shock loading,Uniformity,Wettability,Hardness
更新于2025-09-11 14:15:04
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The Role of the Surface Nano-Roughness on the Wettability Performance of Microstructured Metallic Surface Using Direct Laser Interference Patterning
摘要： Superhydrophobic natural surfaces usually have multiple levels of structure hierarchy, particularly microstructures covered with nano-roughness. The multi-scale nature of such a surface reduces the wetting of water and oils, and supports self-cleaning properties. In this work, in order to broaden our understanding of the wetting properties of technical surfaces, biomimetic surface patterns were fabricated on stainless steel with single and multi-scale periodic structures using direct laser interference patterning (DLIP). Micropillars with a spatial period of 5.5 μm and a structural depth of 4.2 μm were fabricated and covered by a sub-micro roughness by using ultrashort laser pulses, thus obtaining a hierarchical geometry. In order to distinguish the influence of the different features on the wettability behavior, a nanosecond laser source was used to melt the nano-roughness, and thus to obtain single-scale patterns. Then, a systematic comparison between the single- and multi-scale structures was performed. Although, the treated surfaces showed hydrophilic behavior directly after the laser treatment, over time they reached a steady-state hydrophobic condition. However, the multi-scale structured metal showed a contact angle 31° higher than the single-scale geometry when the steady-state conditions were reached. Furthermore, the impact of the surface chemistry was investigated by energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analyses. Finally, a hydrophobizing agent was applied to the laser treated samples in order to further enhance the water contact angles and to determine the pure contribution of the surface topography. In the latter case, the multi-scale periodic microstructures reached static contact angles of 152° ± 2° and a contact angle hysteresis of only 4° ± 2°, while the single-scale structures did not show superhydrophobic behavior. These results definitely suggest that multi-scale DLIP structures in conjunction with a surface chemistry modification can promote a superhydrophobic regime.
关键词： multi-scale microstructures,wettability transition,nanosecond and picosecond laser pulses,direct laser interference patterning
更新于2025-09-11 14:15:04
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Femtosecond-laser-ablation induced transformations in the structure and surface properties of diamond-like nanocomposite films
摘要： Femtosecond laser ablation processing is applied for surface modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H:Si:O films). Using a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs), microgroove patterns have been fabricated on the DLN films, aimed at further studies of their properties. The studies were focused on (i) structural transformations in the surface layers using Raman spectroscopy and transmission electron microscopy (TEM), (ii) wettability of laser-patterned films, and (iii) nano/microscale friction properties of laser-patterned DLN films using lateral force microscopy. Raman spectroscopy and TEM data showed characteristic features of the surface graphitization during ultrashort-pulse ablation. High resolution TEM study of the microgrooves revealed the formation of cubic SiC nanocrystals (4–8 nm size) on the laser-ablated surface. The water contact angle measurements showed anisotropic wetting behavior of the grooved surfaces (the contact angle was different in the directions parallel and perpendicular to microgrooves), depending on the groove depth (aspect ratio). Lateral force microscopy examination (with micro-sized Si tips) showed that the laser-patterned regions exhibited low friction properties compared to the original surface. The obtained results demonstrate that femtosecond laser processing is an effective technique to generate new properties of hard DLN coatings at the micro and macroscale.
关键词： Diamond-like nanocomposite films,Femtosecond laser ablation,Micropatterning,SiC nanocrystals,Graphitization,Wettability
更新于2025-09-11 14:15:04
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Surface with Reversible Green-light-switched Wettability by Donor-Acceptor Stenhouse Adducts
摘要： In this report, we designed surfaces with reversible green-light-switched wettability by Donor-Acceptor Stenhouse adducts (DASAs). Photoresponsive micro/nanoparticles were prepared by coating polydopamine on the surface of silica micro/nanoparticles and then post-modifying with DASA molecules. Then, the particles were immobilized on glass substrates surface either by double-sided adhesive tapes or crosslinking polydimethylsiloxane. Silica micro/nanoparticles with various diameters (0.2, 2.5 and 85 μm) were used to fabricate the photoresponsive surface. Green light irradiation switches the hydrophobic linear DASA to hydrophilic cyclic isomer, which further increases the wettability and contact angle hysteresis on surface. On the other hand, heating (100 oC) induces the cyclic-to-linear isomerization of DASA molecules, and switches the surface back to hydrophobic. The wettability of the DASAs modified surface is reversible under alternately green light irradiating and heating.
关键词： donor-acceptor Stenhouse adducts,green light,surface,photoresponsive system,wettability
更新于2025-09-10 09:29:36
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Photochromic Materials by Postpolymerisation Surface Modification
摘要： Photochromic materials are available by a postpolymerization surface modi?cation of diverse polymers in a multistep sequential process mediated, ?rst, by carbene insertion chemistry, second, by diazonium coupling with a tethered precursor, and ?nally by coupling to a spiropyran. This three-step sequence is e?cient, and surface loading densities of 1013 molecules cm?2 are typically achievable, leading to materials with observable photochromic and wettability behavior, which operate over multiple cycles without signi?cant photobleaching or loss of e?cacy. Materials suitable for application in this process include both reactive, but also lower surface energy polymers. Although the process is particularly e?cient for high surface area materials, surface modi?cation onto lower surface area substrates, while being intrinsically less e?cient, is nonetheless su?ciently e?ective that changes in macroscopic photochromic properties are readily observable.
关键词： wettability behavior,carbene insertion chemistry,Photochromic materials,postpolymerization surface modi?cation,spiropyran,diazonium coupling
更新于2025-09-10 09:29:36
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Surface micro-structuring of type 304 stainless steel by femtosecond pulsed laser: effect on surface wettability and corrosion resistance
摘要： This paper presents results on femtosecond (fs) pulsed laser-based surface micro-structuring of type 304 stainless steel (304 SS). Post laser treatment surface wettability and corrosion resistance investigation are reported. SS sample surfaces have been micro-structured using a typical laser fluence of ~ 0.9 J/cm2 for varying sample scanning speed in the range 25–1000 μm/s. Dense array of micro-protrusions have been generated without formation of a crater for an optimized target scan speed exceeding 200 μm/s. Static water contact angle (WCA) measurement indicated super-hydrophilic behavior immediately after laser treatment. However, hydrophilicity (wettability) was found to decrease with storage time with sample becoming highly hydrophobic (WCA: 144° ± 5°) within 50 days after laser treatment. Corrosion resistance of the laser-treated samples was measured by potentio-dynamic polarization technique. Fs laser micro-structured SS has shown poorer corrosion resistance in comparison to pristine surface. Observed poorer corrosion resistance of laser-treated surface has been explained on the basis of surface chemical composition and surface roughness. The results demonstrated that corrosion resistance increased with increasing hydrophobicity of the SS surface.
关键词： corrosion resistance,femtosecond pulsed laser,stainless steel,surface micro-structuring,wettability
更新于2025-09-10 09:29:36