scholarly journals Nanostructured Materials for the Development of Superhydrophobic Coatings

2021 ◽  
Author(s):  
Jeyasubramanian Kadarkaraithangam ◽  
Thangaiyanadar Suyambulingam Gokul Raja ◽  
Silambuselvan Parani Bramma Nayagi ◽  
Karthikeyan Krishnamoorthy
Keyword(s):  
Spray Coating ◽  
Underwater Robotics ◽  
The Novel ◽  
Zno Nanostructures ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Method ◽  
Biomedical Coatings ◽  
Self Cleaning ◽  
Novel Applications

This chapter describes the results of developing superhydrophobic coatings using porous ZnO nanostructures impregnated metal stearates and their applications. The porous ZnO nanostructures with a surface area of 9.7 m2/g and pores in the range from 200 to 400 nm have been prepared via precipitation cum calcination route. The superhydrophobic coatings comprising ZnO/metal stearate film have been deposited using a spray coating method. The developed superhydrophobic films possess a water contact angle of 161° that can be explained using the Cassie-Baxter model. The prepared films exhibited excellent floating properties and high load-bearing characteristics over a prolonged time. Additionally, the self-cleaning properties of the developed superhydrophobic films towards dust removal and self-cleaning urinary coatings are also demonstrated. This chapter collectively presented the novel applications of superhydrophobic coating in the development of biomedical coatings and applications in water surveillance and underwater robotics.

scholarly journals High Transmittance Superhydrophobic Coatings with Durable Self-Cleaning Properties

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 493
Author(s):  
Michele Ferrari ◽  
Paolo Piccardo ◽  
Justine Vernet ◽  
Francesca Cirisano
Keyword(s):  
Power Plants ◽  
Spray Coating ◽  
Dust Particles ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Spray Method ◽  
Coating Method ◽  
Solar Power Plants ◽  
Self Cleaning ◽  
The Impact

One of the most important factors determining a significant reduction in optical devices’ efficiency is the accumulation of soiling substances such as dust, which, especially in solar power plants, implies higher costs and materials ageing. The use of superhydrophobic (SH) coatings, water contact angle (CA) greater than 150°, represents a suitable solution to improve the self-cleaning action while at the same time providing high transmittance for energy conversion. A mixed organic–inorganic SH coating with surface roughness below 100 nm was prepared by an easily scalable spray method and employed, allowing us to modulate the covered area and transparency. The coating has been also investigated while simulating pollution agents like acid rain, harsh environments, and the impact of continuous water droplets and dust particles with different physicochemical properties. The spray coating method allows us to obtain a modulated SH and self-cleaning surface showing CA > 170°, high transmittance in UV-Vis range and the ability to completely restore its initial properties in terms of wettability and transmittance after durability and soiling tests.

scholarly journals Development of a Stable TiO2Nanocomposite Self-Cleaning Coating for Outdoor Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
F. Madidi ◽  
G. Momen ◽  
M. Farzaneh
Keyword(s):  
Mechanical Stability ◽  
Low Cost ◽  
Spray Coating ◽  
Dielectric Behavior ◽  
Superhydrophobic Coatings ◽  
Angle Measurements ◽  
Coating Method ◽  
Specific Frequency ◽  
Self Cleaning ◽  
The Stability

A convenient and low-cost approach for the elaboration of a stable superhydrophobic coating is reported, involving the use of TiO2nanoparticles via the spray coating method. This method can be used for preparing self-cleaning superhydrophobic coatings on large areas for different kinds of substrates. The synergistic effect of the micro/nanobinary scale roughness was produced by a multilayer RTV SR/TiO2composite. The influence of the nanofiller concentration in a specific frequency range (40 Hz to 2 MHz) on the dielectric behavior was analyzed as well. It was found that the real relative permittivity (εr′) increases as the nanofiller concentration increases. Superhydrophobic behavior is analyzed by contact angle measurements, scanning electron microscopy (SEM), and profilometer. The stability of the developed coating also has been evaluated in terms of immersion in various aqueous solutions, heating, adhesion, and exposure to UV irradiation, and the results showed good stability against these factors. The coating retained its superhydrophobicity after several days of immersion in solutions of different pH levels (2, 4, 6, and 12) and different conductivities. In addition, they also exhibited exceptional stability against UV radiation and heating, as well as good mechanical stability.

scholarly journals Stable and Durable Conductive Superhydrophobic Coatings Prepared by Double-Layer Spray Coating Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1506
Author(s):  
Xiang Liu ◽  
Kai Chen ◽  
Dekun Zhang ◽  
Zhiguang Guo
Keyword(s):  
Composite Coating ◽  
Double Layer ◽  
Low Cost ◽  
Spray Coating ◽  
Sliding Angle ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Method ◽  
Specialty Fields ◽  
Application Fields

Herein, a low cost, durable, and stable conductive superhydrophobic composite coating (CSC coating) was fabricated on a Q345 steel surface by simple double-layer spray coating. The water contact angle (WCA) of the CSC coating was 160° and the sliding angle (SA) was 3°. In addition to its excellent conductivity (3.10 × 103 Ω), the fabricated composite coating had good durability and wear resistance. After 10 sand-washing cycles, the CSC coating surface still exhibited stable superhydrophobicity (149° WCA, 9.5° SA). At 200 g pressure, the surface of the optimized CSC coating still maintained fine superhydrophobicity (150° WCA, 9.2° SA) and conductivity (1.86 × 104 Ω) after 10 abrasion cycles. In addition, it also exhibited fine adhesion (0.307 MPa) between the composite coating and the substrate. This functional superhydrophobic surface can be applied in specialty fields with harsh conditions such as coal mining and petrochemical activities. This new coating may also expand the application fields of superhydrophobic surfaces and have broad practical application prospects.

Effect of Stirring on Hydrophobicity of PVDF/CNT Nanocomposite Coatings

2014 ◽  
Vol 938 ◽  
pp. 199-203 ◽  
Author(s):  
G. Prasad ◽  
Arun Anand Prabu
Keyword(s):  
Phase Separation ◽  
Polyvinylidene Fluoride ◽  
Fluorine Content ◽  
Spray Coating ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Method ◽  
Stirring Time ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs)-Polyvinylidene fluoride (PVDF) superhydrophobic coatings were prepared by a facile phase separation and spray coating method. The effect of phase separation and stirring on wettability has been studied. A transformation of hydrophobic to super-hydrophobic state is achieved with increasing CNT content. In the absence of CNTs, the neat PVDF coatings exhibited water contact angle (WCA) of 105o. A gradual increase in WCA is observed with increasing addition of CNTs, and reaches to super-hydrophobic state (WCA > 150o) for CNT content of 33%. FTIR studies revealed a stronger interaction between PVDF and CNT with increasing stirring time. FESEM images and EDAX data show uniform morphology and higher fluorine content, respectively for samples stirred for longer time when compared to shorter stirring time, and the results are discussed in detail.

Fabrication of ZnO Nanostructures with Self-Cleaning Functionality

2011 ◽  
Vol 364 ◽  
pp. 100-104 ◽  
Author(s):  
Kuan Ying Kok ◽  
Inn Khuan Ng ◽  
Nur Ubaidah Saidin ◽  
Farah Khuwailah Ahmad Bustamam
Keyword(s):  
Chemical Properties ◽  
Structural Features ◽  
Zno Films ◽  
Zno Nanostructures ◽  
Water Contact ◽  
One Dimensional ◽  
Glass Substrates ◽  
Electrochemically Deposited ◽  
Superhydrophobic Property ◽  
Self Cleaning

The science of biomimicry has served as a fusion point between nature and technology where one could adopt nature’s best solution for human’s use. Lotus leaf, for example, possesses self-cleaning capability due to the unique physical and chemical properties of its surface structural features. In this work, we aimed to mimic these features on glass surface using ZnO nanostructures to achieve the self-cleaning functionality. A series of ZnO films were electrochemically deposited on indium-doped tin oxide (ITO) conducting glass substrates from different aqueous electrolytes at systematically varied deposition potentials and electrolyte conditions. The surface morphology, density, orientation and aspect ratio of the ZnO micro/nanostructures obtained were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). ZnO ranging from two dimensional plate-like to one-dimensional needle-like micro/nanostructures were observed. Results from these studies show that lower electrolyte concentrations tend to favor one-dimensional growth of ZnO nanostructures that self-assembled into micron-size flower-like clusters at higher deposition temperatures. The ZnO-modified hierarchical dual-structured surface exhibits superhydrophobic property with water contact angle as high as 170o.

scholarly journals Superhydrophobic and photocatalytic self-cleaning on cotton fabric using fluorine-free flower-like-TiO2/PDMS coatings

2021 ◽  
Author(s):  
Esfandiar Pakdel ◽  
Hai Zhao ◽  
Jinfeng Wang ◽  
Bin Tang ◽  
Russell Varley ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Cotton Fabric ◽  
Nitrogen Doping ◽  
Dip Coating ◽  
Polydimethyl Siloxane ◽  
Water Contact ◽  
Highly Efficient ◽  
Coating Method ◽  
Self Cleaning ◽  
The Impact

Abstract This research presents the development of novel self-cleaning cotton fabric with dual functionalities of superhydrophobicity and photocatalytic activity. Fluorine-free coating formulations composed of either flower-like TiO2 or nitrogen-doped TiO2 particles, with a hierarchical surface morphology, and polydimethyl siloxane (PDMS) polymer were applied to cotton fabrics using a facile dip-coating method. The self-cleaning performance of fabrics was assessed based on their superhydrophobicity and effective removal of oil-based food stains. Additionally, the impact of nitrogen doping on photocatalytic activity of flower-like TiO2 particles was investigated. The obtained results demonstrated that the presence of both PDMS and hierarchical particles generated excellent superhydrophobicity on the cotton fabric with a water contact angle of 156.7 ± 1.9⁰. In addition, the coated fabric exhibited highly efficient photocatalytic activity, decomposing stains under simulated sunlight. Nitrogen doping process significantly boosted the photocatalytic activity of TiO2 particles in degrading stains and dye solution. The developed superhydrophobic fabric showed high robustness against both chemical and physical durability tests. This research contributes significantly to the continued advancement of highly efficient self-cleaning textiles via the development of dual functions of superhydrophobicity and photocatalytic activity.

scholarly journals Functional Superhydrophobic Coating Systems for Possible Corrosion Mitigation

2020 ◽  
Vol 14 (2) ◽  
pp. 148-158 ◽  
Author(s):  
Sarah F. Jurak ◽  
◽  
Emil F. Jurak ◽  
Md. Nizam Uddin ◽  
Ramazan Asmatulu
Keyword(s):  
Sol Gel ◽  
Chemical Vapor ◽  
Layer By Layer ◽  
Superhydrophobic Coating ◽  
Sliding Angle ◽  
One Pot ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Run Off ◽  
Self Cleaning

Because of their repellent, corrosion-mitigating, anti-icing, and self-cleaning properties, superhydrophobic coatings have numerous applications from windshields to textiles. A superhydrophobic coating is defined as one having a water contact angle (WCA) greater than 150° with a surface sliding angle less than 10°, and very low hysteresis between the advancing and receding angles. Its surface exhibits the so-called “lotus leaf effect,” whereby water bounces and balls up on contact. Here, water droplets run off readily, taking along dirt and dust for a self-cleaning effect that keeps the surface dry. The chemical composition of a surface affects the WCA, which can rise to 120°, but to achieve a WCA greater than 150°, which is considered superhydrophobic, an additional micro- and nanostructural component is needed. This functional hierarchical micro- and nanomorphology is exhibited in nature by plants and insects. A superhydrophobic coating on metallic substrates promises to provide corrosion mitigation by blocking oxygen and electrolytes, which are needed for the initiation of corrosion at the surface and interface. The methods used for preparing functional superhydrophobic coatings include sol-gel processing, layer-by-layer assembly, etching, lithography, chemical and electrochemical depositions, chemical vapor deposition, electrospinning, hydrothermal synthesis, and one-pot reactions. In this work, some research studies conducted to develop robust and durable superhydrophobic coatings are discussed in detail and analyzed for possible corrosion mitigation on the surfaces of metals and alloys. Scientists, engineers, students, and other participants in automotive, aircraft, energy, defense, electronics, and other industries will benefit greatly from this work.

scholarly journals Preparation and Self-Cleaning Performance of Carbon-Based Superhydrophobic Coatings Based on Non-Fluorine and Non-Toxic Corn Straw

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6401
Author(s):  
Yanbin Wang ◽  
Lihui Kang ◽  
Zhaoxia Li ◽  
Qiong Su ◽  
Shaofeng Pang ◽  
...  
Keyword(s):  
Hierarchical Structures ◽  
Dip Coating ◽  
Industrial Applications ◽  
Raw Material ◽  
Corn Straw ◽  
Water Contact ◽  
Carbon Particles ◽  
Cleaning Performance ◽  
Superhydrophobic Coatings ◽  
Self Cleaning

Recently, superhydrophobic surfaces with self-cleaning ability have attracted broad research interest due to their huge potential in daily lives and industrial applications, but the use of fluorinate, toxic organic compounds, and expensive feedstocks make superhydrophobic materials a great challenge in practical application. In this study, we present a facile dip-coating strategy to prepare superhydrophobic coatings with self-cleaning properties based on a non-fluorine and non-toxic system by using eco-friendly corn straw as raw material. During this process, aromatic carbon particles with rough hierarchical structures were prepared firstly via a simple fast pyrolysis process, followed by modification with polydimethylsiloxane (PDMS) in absolute ethanol solvent to decrease the surface free energy. Research shows these natural straw-derived carbons display a microstructure of several protrusions which is similar to the lotus leave’s and the resulted coatings exhibit an outstanding superhydrophobic property with a static water contact angle (WCA) of 151.67 ± 1.36 degrees. In addition, the as-prepared coatings possessed excellent self-cleaning performance: no contaminations were observed on the surfaces after examining with sludge, calcimine, water, and common liquids such as tea, milk, soybean milk as well as ink, which have a broad range of potential application in the field of antifouling, waterproofing, and anticorrosive.

scholarly journals Silica Based Superhydrophobic Nanocoatings for Natural Rubber Surfaces

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Veromee Kalpana Wimalasiri ◽  
Helapiyumi Uthpala Weerathunga ◽  
Nilwala Kottegoda ◽  
Veranja Karunaratne
Keyword(s):  
Natural Rubber ◽  
Imaging Techniques ◽  
Spray Coating ◽  
Surface Functional Groups ◽  
Sliding Angle ◽  
Water Contact ◽  
Force Microscopy ◽  
Superhydrophobic Coatings ◽  
Atomic Force ◽  
Coating Methods

Silica based nonfluorinated superhydrophobic coatings for natural rubber surfaces have been developed. The coating was synthesized using nanosilica dispersion and a polychloroprene type binder as a compatibilizer. This nanocoating of silica was applied on to the surface of finished natural rubber gloves, by spray coating or dipped coating methods. The nanocoating demonstrates a water contact angle of more than 150° and sliding angle of 7°. The morphological features of the coating have been studied using scanning electron microscopy and atomic force microscopy while Fourier transform infrared spectroscopy was used to understand the nature of surface functional groups. Both imaging techniques provided evidence for the presence of nanosized particles in the coating. Coated gloves demonstrated comparable mechanical properties and significantly better alcohol resistivity when compared to those of the uncoated gloves.

scholarly journals Dip-Coating Approach to Fabricate Durable PDMS/STA/SiO2 Superhydrophobic Polyester Fabrics

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 326
Author(s):  
Xiaoli Liu ◽  
Youcai Gu ◽  
Tengfei Mi ◽  
Xiaomei Wang ◽  
Xu Zhang
Keyword(s):  
Contact Angle ◽  
Textile Industry ◽  
Dip Coating ◽  
Water Contact ◽  
Force Microscopy ◽  
Superhydrophobic Coatings ◽  
Atomic Force ◽  
High Durability ◽  
Coating Method ◽  
Dip Coating Method

The facile, simple, highly efficient, and fluorine-free fabrication of superhydrophobic surfaces on fabrics with high durability has attracted considerable attention because of its urgent practical application. The simple dip-coating method was adopted to make a stable and durable polydimethylsiloxane/stearic acid/silica (PDMS/STA/SiO2) superhydrophobic fabric. The fabric’s surface morphology, roughness, and composition were analyzed by scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy, respectively. The PDMS/STA/SiO2-coated fabric: demonstrated strong superhydrophobicity (a water contact angle (WCA) of around 163°), efficiently repelled different liquids (milk, coffee, orange juice, Coca-Cola, and 1 M of HCl and NaOH) with a contact angle above 155°, had excellent self-cleaning performance, and retained superhydrophobicity with a WCA greater than 150° after 72 h of ultraviolet irradiation and 700 cycles of mechanical abrasion. The PDMS/STA/SiO2 coating had few influences on the color fastness of the fabric. Superhydrophobic coatings are expected to be practically applied in the textile industry.

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