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 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 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 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 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.

scholarly journals Reducing the Cost of Energy From Parabolic Trough Solar Power Plants

Solar Energy ◽  
2003 ◽  
Author(s):  
Henry Price ◽  
David Kearney
Keyword(s):  
Mojave Desert ◽  
Power Plants ◽  
Large Scale ◽  
Solar Power ◽  
Parabolic Trough ◽  
Cost Of Energy ◽  
Solar Power Plants ◽  
The Cost ◽  
The Impact ◽  
Fossil Fuel Power Plants

Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power from conventional fossil fuel power plants. This paper reviews the current cost of energy and the potential for reducing the cost of energy from parabolic trough solar power plant technology based on the latest technological advancements and projected improvements from industry and sponsored R&D. The paper also looks at the impact of project financing and incentives on the cost of energy.

scholarly journals Study on Dust Deposition Mechanics on Solar Mirrors in a Solar Power Plant

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4550 ◽  
Author(s):  
Xueqing Liu ◽  
Song Yue ◽  
Luyi Lu ◽  
Jianlan Li
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Renewable Energy Sources ◽  
Dust Particles ◽  
Particle Collision ◽  
Energy Sources ◽  
Solar Power Plant ◽  
Dust Deposition ◽  
Research Results ◽  
Solar Power Plants

Solar energy is considered to be one of most promising renewable energy sources because of its availability and cleanliness. The phenomenon of dust deposition on solar mirrors greatly reduces the power generation of solar power plants. In this work, the motion behaviors and deposition mechanics of dust particles are analyzed by the discrete element method (DEM). The effects of environmental and solar mirror conditions and particle self-factors on dust deposition weight are systematically studied here. The research results show that dust particles, after particle collision, immediately adhere to the mirror or rebound and finally flow away from the mirror, or they otherwise may remain stationary after making some relative motion. Alternatively, they may glide for some distance and finally come to rest on the mirror or leave from the system. Different motion behaviors after particle collision depend on different leading forces. Here, the leading forces are the liquid bridge force (Fc) and the contact force (Fb). When the leading forces are Fc, or Fc, and Fb, the dust particles will be deposited on the solar mirror. Besides, the force Fc cannot be negligible when studying the motion processes of dust particles. The dust deposition weight on solar mirrors can be controlled by altering the environmental and solar mirror conditions, and particle self-factors. In essence, dust deposition weight on solar mirrors decreases when decreasing the leading force Fc or increasing the leading force Fb. The research results give theoretical guidance for the prevention and removal of dust deposition on solar mirrors.

scholarly journals Preparation of CNF/PDMS Superhydrophobic Coatings with Good Abrasion Resistance Using a One-Step Spray Method

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5380
Author(s):  
Jingda Huang ◽  
Peihao Cai ◽  
Mengmeng Li ◽  
Qiang Wu ◽  
Qian Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Abrasion Resistance ◽  
Substrate Surface ◽  
Cellulose Nanofibers ◽  
Scratch Resistance ◽  
Water Contact ◽  
Preparation Methods ◽  
Superhydrophobic Coatings ◽  
Spray Method ◽  
Complex Preparation

Complex preparation methods and weak mechanical properties of superhydrophobic coatings hinder their applicability. To address these problems, cellulose nanofibers (CNFs) were used as structural materials to augment the roughness properties, while polydimethylsiloxane (PDMS) was used as the adhesive. Based on the results of previous studies, superhydrophobic coatings with good mechanical properties can be prepared by spraying the mixture onto a substrate surface; herein, the mixture comprised modified CNFs and PDMS. The resulting coating possessed excellent superhydrophobicity, which allowed a maximum water contact angle (WCA) of 158°. Furthermore, it exhibited great knife-scratch-resistance properties and good abrasion performance, which was evaluated by abrading with 800-grit sandpaper for 19 cycles (abrasion length of 380 cm) under a 100 g load. Based on the simple operation and abrasion resistance, the coating shows great potential for practical application.

scholarly journals Reduced Graphene Oxide Filtration Membranes for Dye Removal—Production and Characterization

2020 ◽  
Vol 4 (1) ◽  
pp. 29
Author(s):  
Andreza Lima ◽  
Anthony de Oliveira ◽  
Luana Demosthenes ◽  
Talita Sousa ◽  
Artur Pereira ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Textile Industry ◽  
Dye Removal ◽  
Low Cost ◽  
Spray Coating ◽  
Filtration Membranes ◽  
Spray Method ◽  
Reduced Graphene ◽  
Coating Method

Dye removal from manufacturing and textile industry wastewater is one of the biggest challenges in plants. The improper disposal of water with residual dyes can contaminate effluents and fresh water sources. In this work, filtration membranes based on reduced graphene oxide (rGO) were fabricated by the spray coating method, and its capability to remove dyes from water was evaluated. Graphene oxide was prepared by a modified Hummers method and posteriorly reduced with ascorbic acid; a simple and fast spray coating fabrication method was employed to produce stable membranes, which were analyzed in a home-made permeation cell. Raman spectroscopy and scanning electron microscopy (SEM) were able to prove that rGO dispersion was formed by graphene flakes with about 45.9 μm of lateral dimension; X-ray diffraction, SEM and Raman analyses indicate that the spray method was efficient in producing stable and uniform filtration membranes; and UV-vis absorption spectra of feed and permeation solution indicate that rGO membranes were capable in removing dye from water. By the main results, it is possible to affirm that rGO filtration membranes are an efficient, low-cost, scalable and fast way to remove dyes from wastewater.

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.

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