Fabrication and Wettability Analysis of Hydrophobic Stainless Steel Surfaces With Microscale Structures From Nanosecond Laser Machining

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Cong Cui ◽  
Xili Duan ◽  
Brandon Collier ◽  
Kristin M. Poduska
Keyword(s):  
Stainless Steel ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Surface Structures ◽  
Laser Machining ◽  
Nanosecond Laser ◽  
Static Contact ◽  
Submicron Structures ◽  
Steel Surfaces ◽  
Hierarchical Multiscale

In this work, nanosecond laser machining is used to fabricate hydrophobic 17-4 PH stainless steel surfaces with microscale and submicron structures. Four surface structures were designed, with microscale channels and pillars (100 μm pitch size) of uniform heights (100 μm) or alternating heights (between 100 μm and 50 μm). During fabrication, the high-power laser beams also created submicron features on top of the microscale ones, leading to hierarchical, multiscale surface structures. Detailed wettability analysis was conducted on the fabricated samples. Measured static contact angles of water on these surfaces are over 130 deg without any coating, compared to ∼70 deg on the original steel surface before laser machining. Slightly lower contact angle hysteresis was also observed on the laser machined surfaces. Overall, these results agree with a simple Cassie–Baxter model for wetting that assumes only fractional surface area contact between the droplet and the surface. This work demonstrates that steel surfaces machined with relatively inexpensive nanosecond laser can achieve excellent hydrophobicity even with simple microstructural designs.

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 Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

The Surface Modification with Fluorocarbon Thin Films for the Prevention of Stiction in Mems

1998 ◽  
Vol 518 ◽  
Author(s):  
Sang-Ho Lee ◽  
Myong-Jong Kwon ◽  
Jin-Goo Park ◽  
Yong-Kweon Kim ◽  
Hyung-Jae Shin
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Fluorocarbon Films ◽  
Perfluorodecanoic Acid ◽  
Large Hysteresis ◽  
Static Contact ◽  
Receding Contact ◽  
Highly Hydrophobic ◽  
Receding Contact Angle

AbstractHighly hydrophobic fluorocarbon films were prepared by the vapor phase (VP) deposition method in a vacuum chamber using both liquid (3M's FC40, FC722) and solid sources (perfluorodecanoic acid (CF3(CF2)8COOH), perfluorododecane (C12F26)) on Al, Si and oxide coated wafers. The highest static contact angles of water were measured on films deposited on aluminum substrate. But relatively lower contact angles were obtained on the films on Si and oxide wafers. The advancing and receding contact angle analysis using a captive drop method showed a large contact angle hysteresis (ΔH) on the VP deposited fluorocarbon films. AFM study showed poor film coverage on the surface with large hysteresis. FTIR-ATR analysis positively revealed the stretching band of CF2 groups on the VP deposited substrates. The thermal stability of films was measured at 150°C in air and nitrogen atmospheres as a function of time. The rapid decrease of contact angles was observed on VP deposited FC and PFDA films in air. However, no decrease of contact angle on them was observed in N2.

scholarly journals Superhydrophobic Fabrics with Mechanical Durability Prepared by a Two-Step Plasma Processing Method

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 351 ◽  
Author(s):  
Kosmas Ellinas ◽  
Angeliki Tserepi ◽  
Evangelos Gogolides
Keyword(s):  
Surface Energy ◽  
Plasma Deposition ◽  
Contact Angle Hysteresis ◽  
Plasma Processing ◽  
High Water ◽  
Contact Angles ◽  
Processing Method ◽  
Static Contact ◽  
Mechanical Durability ◽  
Fabric Surface

Most studies on superhydrophobic fabrics focus on their realization using additive manufacturing (bottom-up) techniques. Here we present the direct modification of three different fabrics using a plasma-based method to obtain anti-adhesive and self-cleaning properties. A two-step plasma processing method is used: (a) for the creation of micro-nanoscale features on the fabric surface (plasma texturing step) and (b) the minimization of the fabric surface energy (by a short plasma deposition step of a very thin, low surface energy layer). The entire process takes only 14 min and all fabrics after processing exhibit high water static contact angles (WSCA > 150°), low contact angle hysteresis (CAH < 7°) and advantageous mechanical durability against hand-rumpling. The method is simple and generic, and it can be therefore expanded to other polymeric fabrics (i.e., acrylic) in addition to polyester, without any limitation rising from the weaving characteristics of the fabric or the starting nature of the material (i.e., hydrophobic or hydrophilic).

Nanoengineered Superhydrophobic Surfaces to Prevent Adhesion of Listeria monocytogenes for Improved Food Safety

2020 ◽  
Vol 63 (5) ◽  
pp. 1401-1407
Author(s):  
Bog Eum Lee ◽  
Youngsang You ◽  
Won Choi ◽  
Eun-mi Hong ◽  
Marisa M. Wall ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Electrochemical Etching ◽  
Contact Angles ◽  
Bacterial Attachment ◽  
Superhydrophobic Surfaces ◽  
List Type ◽  
Ptfe Film ◽  
Steel Surfaces

HighlightsNanoporous superhydrophobic surfaces were fabricated using electrochemical etching and Teflon coating.Adhesion of Listeria monocytogenes to the nanoengineered stainless steel surfaces was reduced.Self-cleanable food-contact surfaces prevent bacterial attachment and subsequent biofilm formation.Abstract. Bacterial attachment on solid surfaces and subsequent biofilm formation is a significant problem in the food industry. Superhydrophobic surfaces have potential to prevent bacterial adhesion by minimizing the contact area between bacterial cells and the surface. In this study, stainless steel-based superhydrophobic surfaces were fabricated by manipulating nanostructures with electrochemical etching and polytetrafluoroethylene (PTFE) film. The formation of nanostructures on stainless steel surfaces was characterized by field emission scanning electron microscopy (FESEM). The stainless steel surfaces etched at 10 V for 5 min and at 10 V for 10 min with PTFE deposition resulted in average water contact angles of 154° ±4° with pore diameters of 50 nm. In addition, adhesion of Listeria monocytogenes was decreased by up to 99% compared to the bare substrate. These findings demonstrate the potential for the development of antibacterial surfaces by combining nanoporous patterns with PTFE films. Keywords: Electrochemical etching, PTFE, Nanoengineered surface, L. monocytogenes, Superhydrophobic.

PREPARATION AND CHARACTERIZATION OF SUPER-HYDROPHOBIC SURFACES ON ALUMINUM AND STAINLESS STEEL SUBSTRATES

2010 ◽  
Vol 17 (03) ◽  
pp. 375-381 ◽  
Author(s):  
ZHIJIA YU ◽  
YUEFEI YU ◽  
YANFENG LI ◽  
SHANPENG SONG ◽  
SUBIN HUO ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Steel Substrate ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Water Contact ◽  
New Feature ◽  
Steel Substrates ◽  
Aluminum Surfaces

Hierarchical alveolate structures in nano- to microscale were fabricated on both aluminum and stainless steel substrates via a chemical etching. On aluminum surfaces, sharp edged caves and plateaus were found. On stainless steel substrate, fine papillae stand on protuberances. These surfaces exhibit super-hydrophobic properties after the fluorination treatment, their water contact angles are 158° and 160°, respectively, with the contact angle hysteresis of about 5°. The roll off angle is about 5°. Ice melting behaviors on a plate of aluminum super-hydrophobic surface were compared with those on a hydrophilic one, their difference shows that the new feature of super-hydrophobic surface could be expected.

Superhydrophobic Surfaces Properties for Anti-Icing

2011 ◽  
Author(s):  
Mohammad Amin Sarshar ◽  
Christopher Swarctz ◽  
Scott Hunter ◽  
John Simpson ◽  
Chang-Hwan Choi
Keyword(s):  
Contact Angle ◽  
Wind Tunnel ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Superhydrophobic Surfaces ◽  
Ice Formation ◽  
Flow Conditions ◽  
Water Droplets ◽  
Dynamic Flow ◽  
Static Contact

In this paper, the iceophobic properties of superhydrophobic surfaces are compared to those of uncoated aluminum and steel plate surfaces as investigated under dynamic flow conditions by using a closed loop low-temperature wind tunnel. Superhydrophobic surfaces were prepared at the Oak Ridge National Laboratory by coating aluminum and steel plates with nano-structured hydrophobic particles. The contact angle and contact angle hysteresis measured for these surfaces ranged from 165–170° and 1–8°, respectively. The superhydrophobic plates along with uncoated control ones were exposed to an air flow of 12 m/s and 20°F with micron-sized water droplets in the icing wind tunnel and the ice formation and accretion were probed by using high speed cameras for 90 seconds. Results show that the developed superhydrophobic coatings significantly delay the ice formation and accretion even with the impingement of accelerated super-cooled water droplets, but there is a time scale for this phenomenon which has a clear relation with contact angle hysteresis of the samples. Among the different superhydrophobic coating samples, the plate having the lowest contact angle hysteresis showed the most pronounced iceophobic effects, while the correlation between static contact angles and the iceophobic effects was not evident. The results suggest that the key parameter for designing iceophobic surfaces is to retain a low contact angle hysteresis, rather than to have only a low contact angle, which can result in more efficient anti-icing properties in dynamic flow conditions.

scholarly journals Thick drops climbing uphill on an oscillating substrate

2018 ◽  
Vol 840 ◽  
pp. 131-153 ◽  
Author(s):  
J. T. Bradshaw ◽  
J. Billingham
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Boundary Integral ◽  
Static Contact Angle ◽  
Rise Velocity ◽  
Contact Lines ◽  
Weakly Nonlinear ◽  
Static Contact

Experiments have shown that a liquid droplet on an inclined plane can be made to move uphill by sufficiently strong, vertical oscillations (Brunet et al., Phys. Rev. Lett., vol. 99, 2007, 144501). In this paper, we study a two-dimensional, inviscid, irrotational model of this flow, with the velocity of the contact lines a function of contact angle. We use asymptotic analysis to show that, for forcing of sufficiently small amplitude, the motion of the droplet can be separated into an odd and an even mode, and that the weakly nonlinear interaction between these modes determines whether the droplet climbs up or slides down the plane, consistent with earlier work in the limit of small contact angles (Benilov and Billingham, J. Fluid Mech. vol. 674, 2011, pp. 93–119). In this weakly nonlinear limit, we find that, as the static contact angle approaches $\unicode[STIX]{x03C0}$ (the non-wetting limit), the rise velocity of the droplet (specifically the velocity of the droplet averaged over one period of the motion) becomes a highly oscillatory function of static contact angle due to a high frequency mode that is excited by the forcing. We also solve the full nonlinear moving boundary problem numerically using a boundary integral method. We use this to study the effect of contact angle hysteresis, which we find can increase the rise velocity of the droplet, provided that it is not so large as to completely fix the contact lines. We also study a time-dependent modification of the contact line law in an attempt to reproduce the unsteady contact line dynamics observed in experiments, where the apparent contact angle is not a single-valued function of contact line velocity. After adding lag into the contact line model, we find that the rise velocity of the droplet is significantly affected, and that larger rise velocities are possible.

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

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.

scholarly journals Large-Beam Picosecond Interference Patterning of Metallic Substrates

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4676
Author(s):  
Petr Hauschwitz ◽  
Dominika Jochcová ◽  
Radhakrishnan Jagdheesh ◽  
Martin Cimrman ◽  
Jan Brajer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser System ◽  
Hierarchical Structures ◽  
High Energy ◽  
Contact Angles ◽  
Surface Structures ◽  
Laser Source ◽  
Metallic Substrates ◽  
And Tungsten

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm2/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

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