A SUPERHYDROPHOBIC COATING ON TITANIUM ALLOYS BY SIMPLE CHEMICAL ETCHING

2021 ◽  
pp. 2150027
Author(s):  
YUFENG ZHANG ◽  
GUOLIANG CHEN ◽  
YAMING WANG ◽  
YONGCHUN ZOU
Keyword(s):  
Contact Angle ◽  
Titanium Alloy ◽  
Electrochemical Impedance ◽  
Contact Angle Hysteresis ◽  
Manufacturing Strategy ◽  
Superhydrophobic Coating ◽  
Sliding Angle ◽  
The Hierarchical Structure ◽  
Silane Modification ◽  
Self Cleaning

In the present study, a scalable-manufactured and environmental-friendly method was proposed to fabricate the superhydrophobic coating on titanium alloy. The hierarchical binary surface structures were obtained by hydrothermal treatment of titanium alloy with oxalic acid and sodium hydroxide solutions successively. The hierarchical structure surfaces after fluoroalkyl-silane modification possessed a maximum contact angle of 158.7° and a sliding angle of 4.3°. The low contact angle hysteresis surface can lead to efficient self-cleaning performance, which was confirmed by the bounce and roll off of water droplet on the surface. Furthermore, the anticorrosion behaviors of the superhydrophobic coating in 3.5[Formula: see text]wt.% NaCl solution was evaluated by the electrochemical impedance spectroscopy (EIS). It was found that the superhydrophobic coating can maintain its superhydrophobic state (150°) within 48 h, thereby effectively preventing the corrosive medium from penetrating into the coating. This simple yet fast anti-corrosion/self-cleaning superhydrophobic coating manufacturing strategy will enlighten its potential application in the engineering fields.

scholarly journals Influence of Abrasive Load on Wettability and Corrosion Inhibition of a Commercial Superhydrophobic Coating

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 887
Author(s):  
Arjun Manoj ◽  
Rahul Ramachandran ◽  
Pradeep L. Menezes
Keyword(s):  
Contact Angle ◽  
Corrosion Inhibition ◽  
Mechanical Stability ◽  
Electrochemical Impedance ◽  
Contact Angle Hysteresis ◽  
Open Circuit ◽  
Superhydrophobic Coating ◽  
Corrosion Properties ◽  
Wetting Properties ◽  
Before And After

The poor mechanical stability of hydrophobic and superhydrophobic surfaces and coatings severely hinder their commercial and industrial applicability. In addition to being expensive and time-consuming to manufacture, the ability of these coatings to maintain their non-wetting properties after mechanical abrasion and wear is currently not well-understood. In this work, the influence of increasing abrasive loads on the roughness, wettability, and corrosion inhibition properties of a commercial superhydrophobic coating was studied. It was shown that the wetting and corrosion properties of the superhydrophobic coating was affected by the abrasive load. Increasing abrasive loads were applied using a tribometer and the electrochemical response was studied using open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The wetting and roughness behavior of the coating before and after the application of the abrasive load was characterized using contact angle, contact angle hysteresis, and optical profilometry. The protective properties of the superhydrophobic coating was observed to deteriorate as the abrasive load increased. Similarly, after a specific abrasive load, the coating transitioned from the Cassie-Baxter state of wetting into that of the Wenzel state.

scholarly journals Durable Superhydrophobic Coating for Efficient Microplastic Removal

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1258
Author(s):  
Oriol Rius-Ayra ◽  
Alisiya Biserova-Tahchieva ◽  
Nuria Llorca-Isern
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Chemical Composition ◽  
High Resolution ◽  
Hierarchical Structure ◽  
Photoelectron Spectroscopy ◽  
Contact Angle Hysteresis ◽  
Superhydrophobic Coating ◽  
Static Contact ◽  
The Hierarchical Structure

The pollution caused by microplastics around the world is an increasingly significant issue that has to be tackled with different methods and technologies. Here, we report a straightforward and rapid process combining electrodeposition and electrophoresis to produce a durable superhydrophobic coating on an aluminum substrate (UNS A91070) that has a static contact angle (153°), sliding angle (1°), and contact angle hysteresis (1°). Field emission scanning electron microscopy and high-resolution transmission electron microscopy showed the presence of a hierarchical structure with nanolayers that were 70 nm thick. The chemical composition was also analyzed using attenuated total reflectance-Fourier transform infrared spectroscopy and high-resolution X-ray photoelectron spectroscopy, which revealed that the hierarchical structure was composed of zinc laurate (Zn(C11H20COO)2) that decreased the surface free energy of the system. Moreover, the coating showed high durability against abrasion caused by the P1200 SiC paper due to the presence of TiO2 particles in the upper layers as well as the homogeneous chemical composition of the hierarchical structure. Finally, taking advantage of the superoleophilic properties of superhydrophobic surfaces, the ability of the coating to remove high-density polyethylene microplastics from water was studied.

scholarly journals Improvement of Surface Roughness and Hydrophobicity in PETG Parts Manufactured via Fused Deposition Modeling (FDM): An Application in 3D Printed Self–Cleaning Parts

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2499 ◽  
Author(s):  
Juan M. Barrios ◽  
Pablo E. Romero
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Flow Rate ◽  
Fused Deposition Modeling ◽  
Light Emitting Diode ◽  
P Value ◽  
Sliding Angle ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Self Cleaning

The fused deposition modeling (FDM) technique is used today by companies engaged in the fabrication of traffic signs for the manufacture of light-emitting diode LED spotlights. In this sector, the surface properties of the elements used (surface finish, hydrophobic features) are decisive because surfaces that retain little dirt and favor self–cleaning behavior are needed. A design of experiments (L27) with five factors and three levels has been carried out. The factors studied were: Layer height (LH), print temperature (T), print speed (PS), print acceleration (PA), and flow rate (F). Polyethylene terephthalate glycol (PETG) specimens of 25.0 × 25.0 × 2.4 mm have been printed and, in each of them, the surface roughness (Ra,0, Ra,90), sliding angle (SA0, SA90), and contact angle (CA0, CA90) in both perpendicular directions have been measured. Taguchi and ANOVA analysis shows that the most influential variables in this case are printing acceleration for Ra, 0 (p–value = 0.052) and for SA0 (p–value = 0.051) and flow rate for Ra, 90 (p–value = 0.001) and for SA90 (p–value = 0.012). Although the ANOVA results for the contact angle are not significant, specimen 8 (PA = 1500 mm/s2 and flow rate F = 110%) and specimen 10 (PA =1500 mm/s2 and F = 100%) have reached contact angle values above or near the limit value for hydrophobia, respectively.

scholarly journals Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

2011 ◽  
Vol 2 ◽  
pp. 66-84 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Contact Angle ◽  
Fluid Flow ◽  
Drag Reduction ◽  
Organic Contaminants ◽  
Contact Angle Hysteresis ◽  
Hierarchical Structures ◽  
Aquatic Animal ◽  
Plant Leaves ◽  
Reduction Efficiency ◽  
Self Cleaning

The emerging field of biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices, and processes which provide desirable properties. Hierarchical structures with dimensions of features ranging from the macroscale to the nanoscale are extremely common in nature and possess properties of interest. There are a large number of objects including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. Certain plant leaves, such as lotus (Nelumbo nucifera) leaves, are known to be superhydrophobic and self-cleaning due to the hierarchical surface roughness and presence of a wax layer. In addition to a self-cleaning effect, these surfaces with a high contact angle and low contact angle hysteresis also exhibit low adhesion and drag reduction for fluid flow. An aquatic animal, such as a shark, is another model from nature for the reduction of drag in fluid flow. The artificial surfaces inspired from the shark skin and lotus leaf have been created, and in this article the influence of structure on drag reduction efficiency is reviewed. Biomimetic-inspired oleophobic surfaces can be used to prevent contamination of the underwater parts of ships by biological and organic contaminants, including oil. The article also reviews the wetting behavior of oil droplets on various superoleophobic surfaces created in the lab.

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 A Durable PVDF/PFOTES-SiO2 Superhydrophobic Coating on AZ31B Mg Alloy with Enhanced Abrasion Resistance Performance and Anti-Corrosion Properties

2021 ◽  
Vol 11 (23) ◽  
pp. 11172
Author(s):  
Zhiqiang Qian ◽  
Zhong Liu ◽  
Shidong Wang ◽  
XiuShen Ye ◽  
Zhijian Wu
Keyword(s):  
Contact Angle ◽  
Wear Resistance ◽  
Salt Spray ◽  
Mg Alloy ◽  
Superhydrophobic Coating ◽  
Friction Test ◽  
Sliding Angle ◽  
Sio2 Coating ◽  
Corrosion Properties ◽  
Water Contact

A simple and practical spray method is employed to prepare a PVDF/PFOTES-SiO2 superhydrophobic composite coating on the AZ31B Mg alloy substrate. The morphology, composition, and water contact angle (CA) were measured by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM) and contact angle measuring instrument. Hydrophilic nano-SiO2 is modified by PFOTES to obtain hydrophobicity. The influence of the mass of PFOTES-SiO2 to PVDF on the hydrophobic properties was studied. The wear resistance and stability of the composite coating have been investigated by immersion test, cross-cut adhesion test and friction test. Additionally, the corrosion resistance was measured by electrochemical workstation and salt spray corrosion test. The CA of PVDF/PFOTES-SiO2 coating is 161.3° and the sliding angle (SAs) is less than 2°. After 10× the sandpaper friction test, the superhydrophobic contact angle of the coating remained above 155°, and the sliding angle was less than 5°, which indicated that the prepared coating is a strong superhydrophobic coating with good wear resistance. The results of the electrochemical tests show that the superhydrophobic coating improved the anti-corrosion performance of Mg alloy, and the water contact angle is greater than 150° after 168 h salt spray corrosion test. Due to its excellent superhydrophobicity, wear resistance and anti-corrosion properties, the robust PVDF/PFOTES-SiO2 coating is considered to have great potential for future applications in the automotive and marine industries.

Controlling the Wetting State With Bio-Mimetic Hierarchical Conical Microstructures

2018 ◽  
Author(s):  
Il Woong Park ◽  
Maria Fernandino ◽  
Carlos Alberto Dorao
Keyword(s):  
Contact Angle ◽  
Geometric Parameter ◽  
Contact Angle Hysteresis ◽  
Apparent Contact Angle ◽  
The Self ◽  
Self Cleaning ◽  
Conical Structures

Achieving a high apparent contact angle with a low contact angle hysteresis represent a major enabling step in applications by the self-cleaning property. In this work, bio-mimetic inspired structures complemented with silanization coating are presented for developing surfaces with a high apparent contact angle with a low contact angle hysteresis. The structures are based on hierarchical conical structures with the different geometric parameter. It was observed that the fabricated surface has high apparent contact angle and low contact angle hysteresis. For that, bio-mimetic texturing of surface and silanization coating can be applied. In this study, hierarchical conical structures were fabricated. The shape of the structures has been inspired from the surface from nature. Moreover, the effect of the silanization coating on the surfaces which has different geometric parameter has been identified.

Micro-Nanostructured Silicone Rubber Surfaces Using Compression Molding

2018 ◽  
Vol 941 ◽  
pp. 1802-1807 ◽  
Author(s):  
Khosrow Maghsoudi ◽  
Gelareh Momen ◽  
Reza Jafari ◽  
Masoud Farzaneh ◽  
Tony Carreira
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Silicone Rubber ◽  
Surface Characterization ◽  
Contact Angle Hysteresis ◽  
Compression Molding ◽  
Sliding Angle ◽  
Water Contact ◽  
Superhydrophobic Property ◽  
Aluminum Surfaces

A facile method is introduced for production of micro-nanostructured silicone rubber surfaces by means of direct replication using a compression molding system. The fabricated samples possessing surface roughness display water contact angle of more than 160o and contact angle hysteresis (CAH) and sliding angle of less than 5o. Such low surface wettability of silicone specimens verifies the induced superhydrophobic property. Chemically etched aluminum surfaces could work excellently as templates whose patterns were replicated on the rubber surfaces successfully. Various etching conditions were examined. Surface characterization techniques revealed the presence of micro-nanostructures on the produced silicone surfaces.

scholarly journals High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Rafik Abbas ◽  
N. Elkhoshkhany ◽  
Ahmed Hefnawy ◽  
Shaker Ebrahim ◽  
Aya Rahal
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sliding Angle ◽  
Water Contact ◽  
Stability Performance ◽  
Graphene Films ◽  
Superhydrophobic Property ◽  
Self Cleaning ◽  
Fluorinated Graphene ◽  
Highly Hydrophobic

A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

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