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 ◽  
...  

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.

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1162
Author(s):  
Rajaram S. Sutar ◽  
Saravanan Nagappan ◽  
Appasaheb K. Bhosale ◽  
Kishor Kumar Sadasivuni ◽  
Kang-Hyun Park ◽  
...  

Superhydrophobic coatings have a huge impact in various applications due to their extreme water-repellent properties. The main novelty of the current research work lies in the development of cheap, stable, superhydrophobic and self-cleaning coatings with extreme water-repellency. In this work, a composite of hydrothermally synthesized alumina (Al2O3), polymethylhydrosiloxane (PMHS) and polystyrene (PS) was deposited on a glass surface by a dip-coating technique. The Al2O3 nanoparticles form a rough structure, and low-surface-energy PHMS enhances the water-repellent properties. The composite coating revealed a water contact angle (WCA) of 171 ± 2° and a sliding angle (SA) of 3°. In the chemical analysis, Al2p, Si2p, O1s, and C1s elements were detected in the XPS survey. The prepared coating showed a self-cleaning property through the rolling action of water drops. Such a type of coating could have various industrial applications in the future.


2021 ◽  
Author(s):  
Esfandiar Pakdel ◽  
Hai Zhao ◽  
Jinfeng Wang ◽  
Bin Tang ◽  
Russell Varley ◽  
...  

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.


2018 ◽  
Vol 14 ◽  
pp. 492-494
Author(s):  
Siti Nur Nazhirah Mazlan ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal

Cost-effective, environmental amiable and maintenance free glasses with improved hydrophobic activity are needed for diverse industrial applications. Pollutant and dirt depositions on glasses that cause the visual obscurity and damages of the cultural heritages require inhibition. The underlying mechanism of hydrophobic interactions assisted self-cleaning traits of glass is poorly understood. It has been shown that excellent hydrophobic glass with water contact angle (WCA) above 90o and very low surface wettability can be achieved by controlling the surface roughness (SR), where liquid droplets remain perfectly spherical on such surfaces (literally without touching) before being self-cleaned (rolls off). Moreover, selection and optimization of constituent materials composition as well as the preparation technique play a significant role towards such success. Most of the previous attempts for the self-cleaning glass preparation were made via coating strategy on glass surface. Yet, preparation of super-hydrophobic glass surfaces with self-cleaning attributes remains an open challenge. Driven by this idea, we prepared a new glass system of composition (80 x) TeO2-20ZnO-(x)SiO2 (x = 0, 0.03, 0.06, 0.09 and 0.12 mol%) by melt-quenching method, where the proportions of SiO2 and TeO2 were interplayed. As-prepared samples (thin pellet without coating) were characterized using atomic force microscopy (AFM) and video contact angle (VCA) measurements. The effects of SiO2 concentration on the glass SR, surface energy and hydrophobic properties were evaluated. Glass 0.06 mol% of SiO2 revealed the optimal WCA of 112.39º and SR of 7.806 nm. It was established that a trade-off between SiO2 and TeO2 contents in the studied glasses could produce super-hydrophobic surface (WCA over 90º), leading to great opportunities for diverse self-cleaning applications.


Author(s):  
Balraj Krishnan Tudu ◽  
Aditya Kumar ◽  
Bharat Bhushan

Durable, superhydrophobic and self-cleaning aluminium surfaces with high corrosion resistance are desirable in many industrial applications. In this study, a facile approach is used to produce aluminium surfaces with superhydrophobicity with a low tilt angle by creating desired roughness structure by immersing in NaOH solution followed by lowering the surface energy by immersing in hexadecyltrimethoxysilane solution. The coated samples show water contact angle of 164 ± 7° and tilt angle of 5 ± 1°. Droplet dynamics of the coated surfaces was investigated. Surfaces exhibited self-cleaning properties. In addition, mechanical, chemical and thermal stability tests were performed. Electrochemical tests of coated surfaces demonstrated anti-corrosion properties with low corrosion current density and high corrosion potential. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.


2018 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
A. Syafiq ◽  
A.K. Pandey ◽  
Vengadaesvaran Balakrishnan ◽  
Nasrudin Abd Rahim

PurposeThe paper aims to investigate the effect of Degussa P-25 Titanium Dioxide (TiO2) nanoparticles on hydrophobicity and self-cleaning ability as a single organic coating on glass substrate.Design/methodology/approachTwo methods have been used to enhance the hydrophobicity on glass substrates, namely, surface modification by using low surface energy isooctyltrimethoxysilane (ITMS) solution and construction of rough surface morphology using Degussa P-25 TiO2nanoparticles with simple bottom-up approach. The prepared sol was applied onto glass substrate using dip-coating technique and stoved in the vacuum furnace 350°C.FindingsThe ITMS coating with nano TiO2pigment has modified the glass substrate surface by achieving the water contact angle as high as 169° ± 2° and low sliding angle of 0° with simple and low-cost operation. The solid and air phase interface has created excellent anti-dirt and self-cleaning properties against dilute ketchup solution, mud and silicon powder.Research limitations/implicationsFindings will be useful in the development of self-cleaning and anti-dirt coating for photovoltaic panels.Practical implicationsSol method provides the suitable medium for the combination of organic–inorganic network to achieve high superhydrophobicity and optimum self-cleaning ability.Originality/valueApplication of blended organic–inorganic sol as self-cleaning and anti-dirt coating film.


2020 ◽  
Vol 14 (2) ◽  
pp. 148-158 ◽  
Author(s):  
Sarah F. Jurak ◽  
◽  
Emil F. Jurak ◽  
Md. Nizam Uddin ◽  
Ramazan Asmatulu

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.


2021 ◽  
Author(s):  
Jeyasubramanian Kadarkaraithangam ◽  
Thangaiyanadar Suyambulingam Gokul Raja ◽  
Silambuselvan Parani Bramma Nayagi ◽  
Karthikeyan Krishnamoorthy

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.


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