Fabrication of titanium-based microstructured surfaces and study on their superhydrophobic stability

2008 ◽  
Vol 23 (9) ◽  
pp. 2491-2499 ◽  
Author(s):  
Baojia Li ◽  
Ming Zhou ◽  
Run Yuan ◽  
Lan Cai
Keyword(s):  
Superhydrophobic Surface ◽  
Contact Angles ◽  
Apparent Contact Angle ◽  
Sliding Angle ◽  
Pillar Array ◽  
Femtosecond Laser Micromachining ◽  
Microstructured Surfaces ◽  
Maximal Deviation ◽  
Four Square ◽  
Titanium Substrates

Based on the classical wetting theories, two theoretically predicted formulas of the apparent contact angles on square-pillar-array microstructured surfaces for Wenzel mode and Cassie mode have been derived, respectively. The theories of superhydrophobic stability on microstructured surfaces have been summarized. Four square-pillar-array samples were fabricated on titanium substrates by using the femtosecond laser micromachining technology, and wettability was analyzed by both experimental and analytical methods. The results showed that the titanium-based surfaces are superhydrophobic. The maximal apparent contact angle is up to 156.9°, while the corresponding sliding angle is 4.7°. Testing of the superhydrophobic stability of the surfaces showed that the maximal deviation of the apparent contact angles is only 0.6°. Analyses indicate that the stable superhydrophobicity of the supplied titanium-based surfaces is within a certain range and not perfect. To improve that, a practical controllable method is proposed herein for the design of a stable superhydrophobic surface.

Superhydrophobicity of Silicon-Based Microstructured Surfaces

2014 ◽  
Vol 989-994 ◽  
pp. 267-269 ◽  
Author(s):  
Gang Li
Keyword(s):  
Contact Angle ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Silicon Surfaces ◽  
Silicon Substrates ◽  
Optical Contact ◽  
Simple Method ◽  
Femtosecond Laser Micromachining ◽  
Microstructured Surfaces ◽  
Silicon Based

Here, a simple method was presented for fabricating superhydrophobic silicon surfaces. Square-pillar-array samples were fabricated on silicon substrates by using the femtosecond laser micromachining technology. We measured the static and dynamic contact angles for water on these surfaces. The contact angles and the rolling angles on the silicon surfaces were measured through an optical contact angle meter. Wettability studies revealed the films exhibited a superhydrophobic behaviour with a higher contact angle and lower rolling angle-a water droplet moved easily on the surface.

scholarly journals Fabrication of elastic, conductive, wear-resistant superhydrophobic composite material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyed Mehran Mirmohammadi ◽  
Sasha Hoshian ◽  
Ville P. Jokinen ◽  
Sami Franssila
Keyword(s):  
Contact Angle ◽  
Composite Material ◽  
Contact Angles ◽  
Wet Etching ◽  
Sliding Angle ◽  
Electrically Conductive ◽  
Wear Resistant ◽  
Nanoscale Structures ◽  
Mechanical Abrasion ◽  
Mechanical Durability

AbstractA polydimethylsiloxane (PDMS)/Cu superhydrophobic composite material is fabricated by wet etching, electroless plating, and polymer casting. The surface topography of the material emerges from hierarchical micro/nanoscale structures of etched aluminum, which are rigorously copied by plated copper. The resulting material is superhydrophobic (contact angle > 170°, sliding angle < 7° with 7 µL droplets), electrically conductive, elastic and wear resistant. The mechanical durability of both the superhydrophobicity and the metallic conductivity are the key advantages of this material. The material is robust against mechanical abrasion (1000 cycles): the contact angles were only marginally lowered, the sliding angles remained below 10°, and the material retained its superhydrophobicity. The resistivity varied from 0.7 × 10–5 Ωm (virgin) to 5 × 10–5 Ωm (1000 abrasion cycles) and 30 × 10–5 Ωm (3000 abrasion cycles). The material also underwent 10,000 cycles of stretching and bending, which led to only minor changes in superhydrophobicity and the resistivity remained below 90 × 10–5 Ωm.

Modeling of Transport During Droplet Deposition and Spreading on Smooth and Microstructured Superhydrophilic Surfaces

2016 ◽  
Author(s):  
Jordan P. Mizerak ◽  
Van P. Carey
Keyword(s):  
Contact Angle ◽  
Contact Angles ◽  
Ansys Fluent ◽  
Effective Contact ◽  
Microstructured Surfaces ◽  
Static Contact ◽  
Droplet Behavior ◽  
Contact Line Pinning ◽  
The Impact ◽  
Superhydrophilic Surfaces

The dynamic behavior of impinging water droplets is studied in the context of varying surface morphologies on smooth and microstructured superhydrophilic surfaces. The goal of this study is to evaluate the capability of contact angle wall adhesion models to accurately produce spreading phenomena seen on a variety of surface types. We analyze macroscale droplet behavior, specifically spreading extent and impinging regime, in situations of varying microscale wetting character and surface morphology. Axisymmetric, volume of fluid (VOF) simulations with static contact angle wall adhesion are conducted in ANSYS Fluent. Simulations are performed on water for low Weber numbers (We<20) on surfaces with features of length scale 5–10μm. Advanced microstructured surfaces consisting of unique wetting characteristics and lengths on each face are also tested. Results show that while the contact angle wall adhesion model shows fair agreement for conventional surfaces, the model underestimates spreading by over 60% for surfaces exhibiting estimated contact angles below approximately 0.5°. Microstructured surfaces adapt the wetting behavior of smooth surfaces with higher effective contact angles based on contact line pinning on morphology features. The propensity of the model to produce Wenzel and Cassie-Baxter states is linked to the spreading radius, introducing an interdependency of microscale wetting and macroscale spreading behavior. Conclusions describing the impact of results on evaporative cooling are also discussed.

Wetting Behavior and Drainage of Water Droplets on Microgrooved Brass Surface

2011 ◽  
Author(s):  
M. A. Rahman ◽  
A. M. Jacobi
Keyword(s):  
Aspect Ratio ◽  
End Milling ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Milling Process ◽  
Water Droplets ◽  
Sliding Angle ◽  
Flat Surfaces ◽  
Micro End Milling ◽  
Water Drops

In the present study, we report the contact angle hysteresis and drainage behavior of water drops on a number of brass surfaces with parallel microgrooves and compare them to the flat baseline surfaces. Parallel micro-grooves with different groove dimensions are fabricated by micro end-milling process without any modification of the surface chemistry. Advancing and receding contact angles in both parallel and perpendicular direction of the grooves and also the drainage behavior of water droplets on the microgrooved surfaces is found to be considerably affected by change in groove geometry parameters. Very high hysteresis is observed for both low (< 0.2) and high aspect ratio (> 0.7) of grooves and also for surfaces with lower groove spacing due to the droplets being in a Wenzel state. For intermediate aspect ratio (0.25–0.70) and larger spacing of the grooves, droplets remain in a Cassie state and the hysteresis is lower in both directions than that on the flat surfaces. Variation of critical sliding angle (angle at the point of incipient sliding of water droplets due to gravity) with groove geometry is investigated for a range of water droplet volume of 15 to 75 μl. Droplets of all volumes are found to slide much more readily on grooved surfaces than when placed on the flat baseline surfaces. Height and spacing of the grooves are also found to have significant influence on the sliding of the water droplets, as critical inclination angle decreased with groove height and increased with groove spacing. The results from this study may be useful in a broad range of applications where water retention plays an important role.

scholarly journals A Durable and Self-Cleaning Superhydrophobic Surface Prepared by Precipitating Flower-Like Crystals on a Glass-Ceramic Surface

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1642
Author(s):  
Haiqing Fu ◽  
Shuo Liu ◽  
Lanlin Yi ◽  
Hong Jiang ◽  
Changjiu Li ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Superhydrophobic Surface ◽  
Three Dimensional ◽  
Strong Acid ◽  
Ceramic Surface ◽  
Sliding Angle ◽  
Water Contact ◽  
Prepared Glass ◽  
Self Cleaning ◽  
Dual Scale

Herein, a superhydrophobic surface with superior durability was fabricated on a glass-ceramic surface by crystallization, hydrofluoric acid (HF) etching, and surface grafting. The as-prepared glass-ceramic surface was composed of three-dimensional flower-like micro-clusters, which were self-assembled from numerous nanosheets. Such a dual-scale rough surface exhibited superhydrophobicity, with a water contact angle (WCA) of 170.3° ± 0.1° and a sliding angle (SA) of ~2° after grafting with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS-17). This can be attributed to the synergistic effect between the dual-scale structure and surface chemistry. Furthermore, this surface exhibited excellent self-cleaning properties, stability against strong acid and strong alkali corrosion, and anti-stripping properties.

scholarly journals Superhydrophobic Surface with Gamma Irradiation Resistance and Self-Cleaning Effect in Air and Oil

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
Yan Zhang ◽  
Jing Zhang ◽  
Yujian Liu
Keyword(s):  
Superhydrophobic Surface ◽  
Water Repellency ◽  
Sio2 Nanoparticles ◽  
Superior Performance ◽  
Sliding Angle ◽  
Water Contact ◽  
Composite Surface ◽  
Static Water Contact Angle ◽  
Static Water ◽  
Dirt Removal

A superhydrophobic surface was synthesized by a combination of an epoxy/polymethylphenylsiloxane matrix and dual-scale morphology of silica (SiO2) nanoparticles. When the amount of SiO2 reached 30 wt.%, the as-prepared surface showed a high static water contact angle (WCA) of 154° and a low sliding angle (SA) of 5°, excellent water repellency, and dirt-removal effects both in air and oil (hexamethylene). Even after exposure to as high as a 12.30 Mrad dose of gamma-rays, the composite surface still maintained its superior performance.

scholarly journals Glaze Icing on Superhydrophobic Coating Prepared by Nanoparticles Filling Combined with Etching Method for Insulators

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Chao Guo ◽  
Ruijin Liao ◽  
Yuan Yuan ◽  
Zhiping Zuo ◽  
Aoyun Zhuang
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Superhydrophobic Surface ◽  
Power Transmission ◽  
Contact Angle Hysteresis ◽  
Transmission System ◽  
Sliding Angle ◽  
Power Transmission System ◽  
Etching Method ◽  
Xps Characterization

Icing on insulators may cause flashover or even blackout accidents in the power transmission system. However, there are few anti-icing techniques for insulators which consume energy or manpower. Considering the water repelling property, the superhydrophobic surface is introduced for anti-icing of insulators. Among the icing forms, the glaze icing owns the highest density, strongest adhesion, and greatest risk to the power transmission system but lacks researches on superhydrophobic surface. In this paper, superhydrophobic surfaces with contact angle of 166.4°, contact angle hysteresis of 0.9°, and sliding angle of less than 1° are prepared by nanoparticle filling combined with etching method. The coated glass slide and glass insulator showed excellent anti-icing performance in the glaze icing test at −5°C. The superhydrophobicity and anti-icing property of the coatings benefit from the low surface energy and hierarchical rough structure containing micron scale pits and nanoscale coralloid bulges supported by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) characterization.

scholarly journals Superhydrophobic Surface by Replication of Laser Micromachined Pattern in Epoxy/Alumina Nanoparticle Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Maciej Psarski ◽  
Jacek Marczak ◽  
Jarosław Grobelny ◽  
Grzegorz Celichowski
Keyword(s):  
Surface Topography ◽  
Plasma Etching ◽  
Superhydrophobic Surface ◽  
Preparation Method ◽  
Nanosecond Laser ◽  
Air Plasma ◽  
Sliding Angle ◽  
Water Contact ◽  
Wet Chemical ◽  
Nanoparticle Agglomerates

Superhydrophobic surfaces were obtained by superposition of microstructure—defined by replication of laser micromachined masters, with nanostructure—created by durable epoxy/γ-Al2O3nanoparticle composite, used for replication. Hierarchical surface topography thus obtained consisted of hexagonally spaced microcavities and nanoparticle agglomerates, exposed on the replica surface by radio frequency (RF) air plasma etching. Surface topography was further enhanced by rims around the microcavity edges, resulting from nanosecond laser micromachining defects in aluminum masters. Subsequent wet chemical hydrophobization with 1H,1H,2H,2H-perfluorotetradecyltriethoxysilane (PFTDTES) provided superhydrophobic behavior in replicas with a microcavity spacing of 30 μm, as indicated by a water contact angle of 160° and a sliding angle of 8°. The preparation method is relatively simple, inexpensive, and potentially scalable.

scholarly journals Fabrication of a Low Adhesive Superhydrophobic Surface on Ti6Al4V Alloys Using TiO2/Ni Composite Electrodeposition

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 121 ◽  
Author(s):  
Jianbing Meng ◽  
Xiaojuan Dong ◽  
Yugang Zhao ◽  
Rufeng Xu ◽  
Xue Bai ◽  
...  
Keyword(s):  
Contact Angle ◽  
Wear Resistance ◽  
Superhydrophobic Surface ◽  
Ph Value ◽  
Chemical Compositions ◽  
Sliding Angle ◽  
Water Contact ◽  
Angle Measurements ◽  
Surface Morphologies ◽  
Composite Electrodeposition

A superhydrophobic surface with low adhesion and good wear resistance was fabricated on Ti6Al4V substrates via TiO2/Ni composite electrodeposition, and subsequently modified with a fluoroalkylsilane (FAS) film. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and optical contact angle measurements were used to characterize the surface morphologies, chemical compositions, and surface wettability. The superhydrophobicity of the as-prepared surface results from the fabrication of a hierarchical structure and the assembly of low-surface energy fluorinated components. The as-prepared surface had a water contact angle as high as 162.6° and a sliding angle close to 1.8°. Scratch and abrasion tests showed that the superhydrophobic coating provided a superior wear resistance and stable mechanical abrasion protection. In addition, the influence of processing conditions, such as working voltage, deposited time, pH value, and TiO2 concentration, was also investigated.

Sign in / Sign up

Export Citation Format

Share Document