Fabrication of superhydrophobic and ice-repellent surfaces on pure aluminium using single and multiscaled periodic textures

Abstract Fabricating aluminium surfaces with superhydrophobic and ice-repellent properties present nowadays a challenging task. In this work, multifunctional structures are manufactured by direct laser writing and direct laser interference patterning methods using pulsed infrared laser radiation (1064 nm). Different periodic patterns with feature sizes ranging from 7.0 to 50.0 µm are produced. In addition, hierarchical textures are produced combining both mentioned laser based methods. Water contact angle tests at room temperature showed that all produced patterns reached the superhydrophobic state after 13 to 16 days. In addition, these experiments were repeated at substrate temperatures from −30 °C to 80 °C allowing to determine three wettability behaviours as a function of the temperature. The patterned surfaces also showed ice-repellent properties characterized by a near three-fold increase in the droplets freezing times compared to the untreated samples. Using finite element simulations, it was found that the main reason behind the ice-prevention is the change in the droplet geometrical shape due to the hydrophobic nature of the treated surfaces. Finally, dynamic tests of droplets imping the treated aluminium surfaces cooled down to −20 °C revealed that only on the hierarchically patterned surface, the droplets were able to bounce off the substrate.

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Direct Laser Interference Patterning of Diffraction Gratings in Safrofilcon-A Hydrogel: Fabrication and Hydration Assessment

Polymers ◽

10.3390/polym13050679 ◽

2021 ◽

Vol 13 (5) ◽

pp. 679

Author(s):

Daniel Sola ◽

Stephan Milles ◽

Andrés F. Lasagni

Keyword(s):

Laser Fluence ◽

Contact Lenses ◽

Laser Source ◽

Spatial Period ◽

Laser Interference ◽

Periodic Patterns ◽

Hydration Properties ◽

Water Contact ◽

Direct Laser ◽

Direct Laser Interference Patterning

Refractive index modification by laser micro-structuration of diffractive optical devices in ophthalmic polymers has recently been applied for refractive correction in the fields of optics and ophthalmology. In this work, Safrofilcon-A hydrogel, used as soft contact lenses, was processed by direct laser interference patterning (DLIP) to fabricate linear periodic patterns on the surface of the samples. Periodic modulation of the surface was attained under two-beam interference by using a Q-switched laser source with emission at 263 nm and 4 ns pulse duration. Features of processed areas were studied as a function of both the interference spatial period and the laser fluence. Optical confocal microscopy used to evaluate the topography of the processed samples showed that both structured height and surface roughness increased with laser fluence. Static water contact angle (WCA) measurements were carried out with deionized water droplets on the structured areas to evaluate the hydration properties of DLIP structures. It was observed that the laser structured areas induced a delay in the hydration process. Finally, microstructural changes induced in the structured areas were assessed by confocal micro-Raman spectroscopy showing that at low laser fluences the polymer structure remained almost unaltered. In addition, Raman spectra of hydrated samples recovered the original shape of areas structured at low laser fluence.

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Multifunctional aluminium surfaces – Laser-structured micropatterns with ice-repellent, superhydrophobic and easy-to-clean properties

MATEC Web of Conferences ◽

10.1051/matecconf/202032604005 ◽

2020 ◽

Vol 326 ◽

pp. 04005

Author(s):

Stephan Milles ◽

Marcos Soldera ◽

Bogdan Voisiat ◽

Andrés Fabián Lasagni

Keyword(s):

Contact Angle ◽

Contact Angle Hysteresis ◽

Contact Angles ◽

Pure Aluminium ◽

Sliding Angle ◽

Water Contact ◽

Static Contact ◽

Direct Laser ◽

Periodic Microstructures ◽

Time Required

In this work, the fabrication of multifunctional periodic microstructures on pure aluminium is presented. Three different geometries were fabricated with feature sizes ranging between 7 µm and 50 µm by using laser-based microstructuring methods. In detail, nanosecond pulsed direct laser writing and picosecond pulsed direct laser interference patterning were used with infrared laser radiation. The wetting characteristics of these structures were investigated performing static water contact angle measurements as well as by measuring the contact angle hysteresis and the sliding angle. The final wetting results show constant static contact angles above 150°, permitting the water droplets to roll off the substrate as well as collecting contamination at the same time. This self-cleaning effect led to a reduction of up to 94% of the spread of 1 µm sized manganese oxide particles. In addition, the freezing time required for droplets laying on the patterned surfaces was increased nearly by 300% at a temperature of 20 °C below zero. Finally, the results are compared to finite element simulations of heat transfer.

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High Throughput Direct Laser Interference Patterning of Aluminum for Fabrication of Super Hydrophobic Surfaces

Materials ◽

10.3390/ma12091484 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1484 ◽

Cited By ~ 3

Author(s):

Valentin Lang ◽

Bogdan Voisiat ◽

Andrés Fabián Lasagni

Keyword(s):

High Throughput ◽

Hydrophobic Surface ◽

Surface Structures ◽

Laser Interference ◽

Heat Accumulation ◽

Water Contact ◽

Laser Beam Intensity ◽

Aspect Ratios ◽

Direct Laser ◽

Direct Laser Interference Patterning

This work addresses the fabrication of hydrophobic surface structures by means of direct laser interference patterning using an optical setup optimized for high throughput processing. The developed optical assembly is used to shape the laser beam intensity as well as to obtain the two sub beams required for creating the interference pattern. The resulting beam profile consists of an elongated rectangular laser spot with 5.0 mm × 0.1 mm size, which enables the optimized utilization of the laser fluence available from an ns-pulsed laser with a wavelength of 1064 nm. Depending on the pulse repetition rate applied, heating of the substrate volume generated by heat accumulation encouraged exceptionally high aspect ratios of the trench structures due to melt flow dynamic material deformation. Finally, water contact angle measurements of the produced structures permitted the demonstration of the capability of controlling the wetting angle, in which this effect does not only depend on the height of the generated surface structures but also on their morphology.

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Stable Superhydrophobic Aluminum Surfaces Based on Laser-Fabricated Hierarchical Textures

Materials ◽

10.3390/ma14010184 ◽

2021 ◽

Vol 14 (1) ◽

pp. 184

Author(s):

Stephan Milles ◽

Johannes Dahms ◽

Marcos Soldera ◽

Andrés F. Lasagni

Keyword(s):

Mechanical Stability ◽

Processing Parameters ◽

Contact Angles ◽

Textured Surfaces ◽

Water Contact ◽

Multi Scale ◽

Static Contact ◽

Direct Laser ◽

Direct Laser Interference Patterning ◽

Microtextured Surfaces

Laser-microtextured surfaces have gained an increasing interest due to their enormous spectrum of applications and industrial scalability. Direct laser interference patterning (DLIP) and the well-established direct laser writing (DLW) methods are suitable as a powerful combination for the fabrication of single (DLW or DLIP) and multi-scale (DLW+DLIP) textures. In this work, four-beam DLIP and DLW were used independently and combined to produce functional textures on aluminum. The influence of the laser processing parameters, such as the applied laser fluence and the number of pulses, on the resulting topography was analyzed by confocal microscopy and scanning electron microscopy. The static long-term and dynamic wettability characteristics of the laser-textured surfaces were determined through water contact angle and hysteresis measurements, revealing superhydrophobic properties with static contact angles up to 163° and hysteresis as low as 9°. The classical Cassie–Baxter and Wenzel models were applied, permitting a deeper understanding of the observed wetting behaviors. Finally, mechanical stability tests revealed that the DLW elements in the multi-scale structure protects the smaller DLIP features under tribological conditions.

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Hierarchical Microtextures Embossed on PET from Laser-Patterned Stamps

Materials ◽

10.3390/ma14071756 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1756

Author(s):

Felix Bouchard ◽

Marcos Soldera ◽

Robert Baumann ◽

Andrés Fabián Lasagni

Keyword(s):

High Speed ◽

Laser Scanning ◽

Contact Angles ◽

Spatial Period ◽

Water Contact ◽

Microscopy Imaging ◽

Drop Shape ◽

Direct Laser ◽

Direct Laser Interference Patterning ◽

Processing Steps

Nowadays, the demand for surface functionalized plastics is constantly rising. To address this demand with an industry compatible solution, here a strategy is developed for producing hierarchical microstructures on polyethylene terephthalate (PET) by hot embossing using a stainless steel stamp. The master was structured using three laser-based processing steps. First, a nanosecond-Direct Laser Writing (DLW) system was used to pattern dimples with a depth of up to 8 µm. Next, the surface was smoothed by a remelting process with a high-speed laser scanning at low laser fluence. In the third step, Direct Laser Interference Patterning (DLIP) was utilized using four interfering sub-beams to texture a hole-like substructure with a spatial period of 3.1 µm and a depth up to 2 µm. The produced stamp was used to imprint PET foils under controlled temperature and pressure. Optical confocal microscopy and scanning electron microscopy imaging showed that the hierarchical textures could be accurately transferred to the polymer. Finally, the wettability of the single- and multi-scaled textured PET surfaces was characterized with a drop shape analyzer, revealing that the highest water contact angles were reached for the hierarchical patterns. Particularly, this angle was increased from 77° on the untreated PET up to 105° for a hierarchical structure processed with a DLW spot distance of 60 µm and with 10 pulses for the DLIP treatment.

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Rapid Fabrication of Periodic Patterns on Poly(styrene-co-acrylonitrile) Surfaces Using Direct Laser Interference Patterning

International Journal of Polymer Science ◽

10.1155/2015/721035 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

Martin F. Broglia ◽

Diego F. Acevedo ◽

Denise Langheinrich ◽

Heidi R. Perez-Hernandez ◽

Cesar A. Barbero ◽

...

Keyword(s):

Laser Fluence ◽

Polymerization Process ◽

Periodic Pattern ◽

Copolymer Composition ◽

Laser Interference ◽

Periodic Patterns ◽

Scanning Calorimetry ◽

Direct Laser ◽

Periodic Microstructures ◽

Direct Laser Interference Patterning

Periodic microstructures in styrene-acrylonitrile (SAN) copolymers are fabricated by two-beam direct laser interference patterning using a nanosecond pulsed laser operating at a wavelength of 266 nm. The SAN copolymers are synthesized using different molar ratios (styrene to acrylonitrile) by a free radical polymerization process. The chemical composition of the copolymers and their properties are determined using Fourier transformed infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Depending on the composition of the irradiated copolymer films, with weight ratios ranging from 58 to 96.5% of styrene to acrylonitrile, different ablation behaviors are observed. The laser fluence necessary to locally ablate the copolymer is found to be dependent on the copolymer composition. Unlike other dielectric polymers, the laser irradiation produced both direct ablation of the irradiated material and collapse of the surface. It is shown that, by varying the laser fluence and the copolymer composition, the surface structure can be changed from a periodic pattern with a swelled topography to an ablated-like structure. The number of holes does not depend monotonically on the amount of PS or PAN units but shows a more complex behavior which depends on the copolymer composition and the laser fluence.

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Improving the homogeneity of diffraction based colours by fabricating periodic patterns with gradient spatial period using Direct Laser Interference Patterning

Scientific Reports ◽

10.1038/s41598-019-44212-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Bogdan Voisiat ◽

Wei Wang ◽

Max Holzhey ◽

Andrés Fabián Lasagni

Keyword(s):

Spatial Period ◽

Laser Interference ◽

Periodic Patterns ◽

Direct Laser ◽

Direct Laser Interference Patterning

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A Fundamental Study of a Surface Modification on Silicon Wafer Using Direct Laser Interference Patterning with 355-nm UV Laser

Science of Advanced Materials ◽

10.1166/sam.2020.3658 ◽

2020 ◽

Vol 12 (4) ◽

pp. 516-519

Author(s):

Dong-Bin You ◽

Jun-Han Park ◽

Bo-Seok Kang ◽

Dan-Hee Yun ◽

Bo Sung Shin

Keyword(s):

Basic Research ◽

Interference Lithography ◽

Uv Laser ◽

Laser Interference ◽

Periodic Patterns ◽

Element Analysis ◽

Fundamental Study ◽

Laser Lithography ◽

Direct Laser ◽

Direct Laser Interference Patterning

The growing need for precision machining, which is difficult to achieve using conventional mechanical machining techniques, has fueled interest in laser patterning. Ultraviolet (UV) pulsed-lasers have been used in various applications, including the micro machining of polymers and metals. In this study, we investigated direct laser interference patterning of a silicon waver using a third-harmonic diode-pumped solid-state UV laser with a wavelength of 355 nm. Direct laser lithography is much more simple process compare to other submicro processing method. We have studied interference patterning for silicon wafers as a basic research for direct laser interference patterning on wafer surfaces without mask. And Finite element analysis (FEA) was performed for a 150° biprism using modeling software (COMSOL Multiphysics 5.4) to determine changes in the periodic patterns according to the focusing distance in the direct interference lithography experiment. In further study, we expect this technique to be applied to direct laser interference lithography on metals.

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Short-Pulse Lasers: A Versatile Tool in Creating Novel Nano-/Micro-Structures and Compositional Analysis for Healthcare and Wellbeing Challenges

Nanomaterials ◽

10.3390/nano11030712 ◽

2021 ◽

Vol 11 (3) ◽

pp. 712

Author(s):

Ahmed Al-Kattan ◽

David Grojo ◽

Christophe Drouet ◽

Alexandros Mouskeftaras ◽

Philippe Delaporte ◽

...

Keyword(s):

Laser Ablation ◽

Surface Engineering ◽

Short Pulse ◽

Chemical Properties ◽

Compositional Analysis ◽

Periodic Patterns ◽

Laser Ablation In Liquid ◽

Micro Scale ◽

Direct Laser ◽

Contact Free

Driven by flexibility, precision, repeatability and eco-friendliness, laser-based technologies have attracted great interest to engineer or to analyze materials in various fields including energy, environment, biology and medicine. A major advantage of laser processing relies on the ability to directly structure matter at different scales and to prepare novel materials with unique physical and chemical properties. It is also a contact-free approach that makes it possible to work in inert or reactive liquid or gaseous environment. This leads today to a unique opportunity for designing, fabricating and even analyzing novel complex bio-systems. To illustrate this potential, in this paper, we gather our recent research on four types of laser-based methods relevant for nano-/micro-scale applications. First, we present and discuss pulsed laser ablation in liquid, exploited today for synthetizing ultraclean “bare” nanoparticles attractive for medicine and tissue engineering applications. Second, we discuss robust methods for rapid surface and bulk machining (subtractive manufacturing) at different scales by laser ablation. Among them, the microsphere-assisted laser surface engineering is detailed for its appropriateness to design structured substrates with hierarchically periodic patterns at nano-/micro-scale without chemical treatments. Third, we address the laser-induced forward transfer, a technology based on direct laser printing, to transfer and assemble a multitude of materials (additive structuring), including biological moiety without alteration of functionality. Finally, the fourth method is about chemical analysis: we present the potential of laser-induced breakdown spectroscopy, providing a unique tool for contact-free and space-resolved elemental analysis of organic materials. Overall, we present and discuss the prospect and complementarity of emerging reliable laser technologies, to address challenges in materials’ preparation relevant for the development of innovative multi-scale and multi-material platforms for bio-applications.

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