scholarly journals One-Step Preparation of Durable Super-Hydrophobic MSR/SiO2 Coatings by Suspension Air Spraying

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 677 ◽  
Author(s):  
Zhengyong Huang ◽  
Wenjie Xu ◽  
Yu Wang ◽  
Haohuan Wang ◽  
Ruiqi Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Adhesion Strength ◽  
Contact Angle Hysteresis ◽  
Surface Hardness ◽  
Hierarchical Structures ◽  
Hydrophobic Surface ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Mechanical Durability ◽  
One Step

In this study, we develop a facial one-step approach to prepare durable super-hydrophobic coatings on glass surfaces. The hydrophobic characteristics, corrosive liquid resistance, and mechanical durability of the super-hydrophobic surface are presented. The as-prepared super-hydrophobic surface exhibits a water contact angle (WCA) of 157.2° and contact angle hysteresis of 2.3°. Mico/nano hierarchical structures and elements of silicon and fluorine is observed on super-hydrophobic surfaces. The adhesion strength and hardness of the surface are determined to be 1st level and 4H, respectively. The coating is, thus, capable of maintaining super-hydrophobic state after sand grinding with a load of 200 g and wear distances of 700 mm. The rough surface retained after severe mechanical abrasion observed by atomic force microscope (AFM) microscopically proves the durable origin of the super-hydrophobic coating. Results demonstrate the feasibility of production of the durable super-hydrophobic coating via enhancing its adhesion strength and surface hardness.

scholarly journals Dynamic Wetting on Moving Surfaces: A Molecular Dynamics Study

2012 ◽  
Author(s):  
Konstantinos Ritos ◽  
Nishanth Dongari ◽  
Yonghao Zhang ◽  
Jason M. Reese
Keyword(s):  
Molecular Dynamics ◽  
Contact Angle ◽  
Capillary Number ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Md Simulations ◽  
Dynamic Wetting ◽  
Water Contact ◽  
Liquid Flows ◽  
Insight Into

We report molecular dynamics (MD) simulations of the dynamic wetting of nanoscale droplets on moving surfaces. The dynamic water contact angle and contact angle hysteresis are measured as a function of capillary number on smooth silicon and graphite surfaces. The hydrogen bonding and density profile variations are also reported, and the width of the water depletion layer is evaluated for droplets on three different static surfaces: silicon, graphite and a fictitious super-hydrophobic surface. Our results show that molecular displacements at the contact line are mostly influenced by interactions with the solid surface, while the viscous dissipation effects induced through the movement of surfaces are found to be negligible, especially for hydrophobic surfaces. This finding is in contrast with the wetting dynamics of macroscale droplets, which show significant dependence on the capillary number. This study may yield new insight into surface-wettability characteristics of nano droplets, in particular, developing new boundary conditions for continuum solvers for liquid flows in micro- and nanoscale devices.

Fabrication of a Super-Hydrophobic Micro-Nanoporous Aluminum Surface by Anodic Oxidation

2012 ◽  
Vol 200 ◽  
pp. 190-193 ◽  
Author(s):  
Ruo Mei Wu ◽  
Shu Quan Liang ◽  
Hong Chen ◽  
An Qiang Pan ◽  
Hai Yun Jiang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Aluminum Surface ◽  
Anodized Aluminum ◽  
Water Contact ◽  
Static Water ◽  
Superhydrophobic Property ◽  
Device Associated Infection

A novel and stable super-hydrophobic film was prepared by stearic acid (C18H36O2), which was chemically adsorbed onto the anodized aluminum surface. The maximum static water contact angle (WCA) of the super-hydrophobic surface was 157.5º ± 2.0º and the contact angle hysteresis was less than 3º. The superhydrophobic property is attributed to the micro-nanoporous surface morphology and stearic acid. The pore size on the surface of anodic aluminum oxide is an important factor for controlling the superhydrophobic adhesiveness. The superhydrophobic surface is a factor to reduce device-associated infection and can be used in metal packaging practice.

A large-scale approach for superhydrophobic coating fabrication

2020 ◽  
pp. 095440542097804
Author(s):  
Ali Ansari ◽  
Nourooz Mohammad Nouri ◽  
Setareh Sekhavat ◽  
Ali Asgari
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Large Scale ◽  
Mixing Time ◽  
Hydrophobic Surface ◽  
Angle Measurement ◽  
Particle Size Range ◽  
Water Contact ◽  
Weight Percentage ◽  
Hydrophobic Coating

Marine structures such as ships, oil platforms, and oceanographic systems are permanently at risk of fouling affecting the performance of these structures. Antifouling paints were used to address the concerns associated to marine organisms, but they release toxic materials. This paper presents a new one-step environmentally friendly super hydrophobic coating considering the effect of particle size as well as weight percentage which is feasible in large-scale applications. Firstly, the aluminum flakes are become hydrophobic using silanization method. Then, they are mixed with polyester triglycidyl isocyanurate (TGIC) and are sprayed electrostatically. To assess the fabricated surfaces, effect of mixing time, weight percentage and particle size on the super hydrophobicity are evaluated using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), contact angle measurement, and image processing. This method leads to a super hydrophobic coating with water contact angle about 152°. The super hydrophobic surface with particle size less than 45 µm results in higher resistance to algae settlement providing an excellent antifouling feature. The uniformity resulted from the particle size range 0–45 µm prevents any micro organisms settlement on the surface so that, after sixth day only some tiny algae are appeared on the surface sides.

Osteoconductivity of Superhydrophilic Ti- and Zr-Alloy for Biomedical Application

2016 ◽  
Vol 879 ◽  
pp. 2524-2527
Author(s):  
Masazumi Okido ◽  
Kensuke Kuroda
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Strong Influence ◽  
Biomedical Application ◽  
Hydrophobic Surface ◽  
Hydrophilic Surface ◽  
Water Contact ◽  
Zr Alloy ◽  
Zr Alloys

Surface hydrophilicity is considered to have a strong influence on the biological reactions of bone-substituting materials. However, the influence of a hydrophilic or hydrophobic surface on the osteoconductivity is not completely clear. In this study, we produced super-hydrophilic and hydrophobic surface on Ti-and Zr-alloys. Hydrothermal treatment at 180 oC for 180 min. in the distilled water and immersion in x5 PBS(-) brought the super-hydrophilic surface (water contact angle < 10 (deg.)) and heat treatment of as-hydrothermaled the hydrophobic surface. The osteoconductivity of the surface treated samples with several water contact angle was evaluated by in vivo testing. The surface properties, especially water contact angle, strongly affected the osteoconductivity and protein adsorbability, and not the surface substance.

scholarly journals A Simple Method to Create Superhydrophobic Aluminium Surfaces

2012 ◽  
Vol 706-709 ◽  
pp. 2874-2879 ◽  
Author(s):  
R. Jafari ◽  
Masoud Farzaneh
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Synergistic Effects ◽  
Low Cost ◽  
Contact Angle Hysteresis ◽  
Spray Coating ◽  
Superhydrophobic Surfaces ◽  
Water Contact ◽  
Simple Method ◽  
Static Contact

Superhydrophobic surfaces were prepared using a very simple and low-cost method by spray coating. A high static water contact angle of about 154° was obtained by deposition of stearic acid on an aluminium alloy. However, this coating demonstrated a high contact angle hysteresis (~ 30º). On the other hand, superhydrophobic surfaces with a static contact angle of about 162º and 158º, and a low contact angle hysteresis of about 3º and 5º were respectively obtained by incorporating nanoparticles of SiO2and CaCO3in stearic acid. The excellent resulting hydrophobicity is attributed to the synergistic effects of micro/nanoroughness and low surface energy. A study of the wettability of these surfaces at temperatures ranging from 20 to-10 °C showed that the superhydrophobic surface becomes rather hydrophobic at supercooled temperatures.

scholarly journals Preparation of Superhydrophobic Steel Surfaces with Chemical Stability and Corrosion

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 398 ◽  
Author(s):  
Chongwei Du ◽  
Xiaoyan He ◽  
Feng Tian ◽  
Xiuqin Bai ◽  
Chengqing Yuan
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Chemical Stability ◽  
Superhydrophobic Surface ◽  
Contact Angle Hysteresis ◽  
Water Contact ◽  
Simple Method ◽  
Q235 Carbon Steel ◽  
Steel Surfaces

Corrosion seriously limits the long-term application of Q235 carbon steel. Herein, a simple fabrication method was used to fabricate superhydrophobic surfaces on Q235 carbon steel for anticorrosion application. The combination of structure and the grafted low-surface-energy material contributed to the formation of superhydrophobic steel surfaces, which exhibited a water contact angle of 161.6° and a contact angle hysteresis of 0.8°. Meanwhile, the as-prepared superhydrophobic surface showed repellent toward different solutions with pH ranging from 1 to 14, presenting excellent chemical stability. Moreover, the acid corrosive liquid (HCl solution with pH of 1) maintained sphere-like shape on the as-prepared superhydrophobic surface at room temperature, indicating superior corrosion resistance. This work provides a simple method to fabricate superhydrophobic steel surfaces with chemical stability and corrosion resistance.

An investigation into the anti-icing properties of fabrics used for the outer layer of firefighter clothing

2018 ◽  
Vol 89 (8) ◽  
pp. 1500-1511 ◽  
Author(s):  
Lun Han ◽  
Xiaoming Zhao ◽  
Jannette Eveline Kidalla
Keyword(s):  
Outer Layer ◽  
Photoelectron Spectroscopy ◽  
Smooth Surface ◽  
Hydrophobic Surface ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Before And After ◽  
Coating Method ◽  
Fabric Surface

The anti-icing properties of fabrics can be considered as involving two parts, the super-hydrophobic property and the ease of ice removal property. In this study, a super-hydrophobic surface was built on to the outer layer of firefighter clothing using nano-silica, C13H13F17O3Si, C19H42O3Si and PU-2540 using a coating method. This coating stops water drops from staying on the fabric surface easily. At the same time, an ultra-smooth surface was built on to the super-hydrophobic surface already created on the fabric using perfluoropolyethers (PFPE) oil by a dipping method, which adds an ice removal function to the fabrics. The anti-icing properties of the samples prepared in the research described in this paper have been investigated using field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), ease of ice removal property tests and static water contact angle analysis. At the same time, the thermal protective performance (TPP) of the samples, before and after super-hydrophobic treatment, was studied by a TPP tester. Results show that the super-hydrophobic coating with an ultra-smooth surface can significantly increase the anti-icing properties of the fabrics used for the outer layer of firefighter clothing. C13H13F17O3Si and C19H42O3Si can improve the hydrophobic properties of the coating. The anti-icing coating in this paper can increase the TPP of the fabrics.

scholarly journals Transparent superhydrophobic PTFE films via one-step aerosol assisted chemical vapor deposition

RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29275-29283 ◽  
Author(s):  
Aoyun Zhuang ◽  
Ruijin Liao ◽  
Sebastian C. Dixon ◽  
Yao Lu ◽  
Sanjayan Sathasivam ◽  
...  
Keyword(s):  
Contact Angle ◽  
Chemical Vapor Deposition ◽  
Water Contact Angle ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Sliding Angle ◽  
Water Contact ◽  
Visible Transmittance ◽  
One Step

Hierarchical micro/nano-structured transparent superhydrophobic polytetrafluoroethylene films with water contact angle 168°, water sliding angle <1° and visible transmittance >90% were prepared on glass via aerosol-assisted chemical vapor deposition.

An Effective Route to the Fabrication of Super-Hydrophobic Surfaces Combined by Micromolding and Photograft Polymerization Methods

2012 ◽  
Vol 152-154 ◽  
pp. 9-13
Author(s):  
Jing Tao Yang ◽  
Lei Wang ◽  
Zheng Yuan Huo ◽  
Jie Feng ◽  
Feng Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Energy Dispersive Spectrometer ◽  
Hydrophobic Surface ◽  
Body Structure ◽  
Critical Difference ◽  
Water Contact ◽  
Methacrylate Monomers ◽  
Polypropylene Matrix ◽  
Morphology Characterization

A super-hydrophobic surface on the polypropylene matrix was fabricated via micromolding and photograft polymerization. A micro-convex body structure was molded by etching templates. The water contact angle could be increased to 138°. The fluoro methacrylate monomers were further grafted to the surface through UV-induced photograft polymerization. The morphology characterization and the spectroanalysis indicated that the rough hierarchical structure (confirmed by scanning electron microscope) and the grafted fluoropolymers (measured by fourier transform infrared spectrum and X-ray energy dispersive spectrometer) made a critical difference. A water contact angle of 160° was arrived.

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.

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