Self-Cleaning Properties, Mechanical Stability, and Adhesion Strength of Transparent Photocatalytic TiO2–ZnO Coatings on Polycarbonate

2014 ◽  
Vol 6 (4) ◽  
pp. 2270-2278 ◽  
Author(s):  
Razan Fateh ◽  
Ralf Dillert ◽  
Detlef Bahnemann
Keyword(s):  
Adhesion Strength ◽  
Mechanical Stability ◽  
Self Cleaning ◽  
Photocatalytic Tio2

Development of polyurethane-based superhydrophobic coatings on steel surfaces

2020 ◽  
Vol 378 (2167) ◽  
pp. 20190446 ◽  
Author(s):  
Mukesh Kumar Meena ◽  
Balraj Krishnan Tudu ◽  
Aditya Kumar ◽  
Bharat Bhushan
Keyword(s):  
Contact Angle ◽  
Steel Surface ◽  
Mechanical Stability ◽  
Industrial Applications ◽  
Angle Measurement ◽  
Coated Steel ◽  
Corrosion Properties ◽  
Static Contact ◽  
Steel Surfaces ◽  
Self Cleaning

In this study, a superhydrophobic coating on steel surface has been developed with polyurethane, SiO 2 nanoparticles and hexadecyltrimethoxysilane by using a spin-coating technique. Characterization of the coated steel surface was done by using the contact angle measurement technique, scanning electron microscopy and Fourier transform infrared spectroscopy. With a water tilt angle of 4° ± 2° and static contact angle of 165° ± 5°, the coated surface shows a superhydrophobic and self-cleaning nature. Chemical, thermal, mechanical stability tests and droplet dynamic studies were done to evaluate performance of the coating. Excellent self-cleaning, anti-fogging and anti-corrosion properties of coated steel surfaces make them ideal for industrial applications. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 3)’.

Iron-doped photocatalytic TiO2 sputtered coatings on plastics for self-cleaning applications

2007 ◽  
Vol 138 (2) ◽  
pp. 144-150 ◽  
Author(s):  
J.O. Carneiro ◽  
V. Teixeira ◽  
A. Portinha ◽  
A. Magalhães ◽  
P. Coutinho ◽  
...  
Keyword(s):  
Iron Doped ◽  
Self Cleaning ◽  
Photocatalytic Tio2

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.

Dry Cationic Friction Reducers: New Alternative for High TDS Slickwater

2021 ◽  
Author(s):  
Linping Ke ◽  
Josselyne Chano ◽  
Melissa Weston ◽  
Hong Sun ◽  
Dong Shen
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Water Treatment ◽  
North America ◽  
Mechanical Stability ◽  
Friction Reduction ◽  
Thermal Testing ◽  
Scale Inhibitor ◽  
Core Flow ◽  
Self Cleaning

Abstract Currently, well stimulation in North America has evolved almost entirely to slickwater fracturing with friction reducers (FRs). Some parts of North America are notorious for their poor water quality, so wells are commonly treated using high total dissolved solids (TDS)-containing flow-back or produced water. Cationic FRs are usually applied in these systems due to their tolerance to multivalent cations in such waters. Additionally, dry friction reducers have gained momentum for better economics and logistics. In this paper, a dry cationic FR is systematically studied with respect to its "on the fly" hydration capability, friction reduction, mechanical stability, compatibility with other anionic chemical additives, and thermal stability in different levels of TDS brines. The cationic FR solution was subjected to varying shearing rates to understand its hydration capability, friction reduction, and mechanical stability. Its compatibility with anionic additives, such as a scale inhibitor, was also tested in a laboratory friction loop. Thermal stability of the cationic FR solution was studied at 150°F using a viscometer and Multi-Angle Laser Light Scattering (MALLS) method to obtain molecular weight information. The charge characteristics of the cationic FR, indicative of self-degradation properties, with exposure to heat, were also studied. Potential formation damage of the FR solution was evaluated with core flow tests in the absence of oxidizing breakers. Friction reduction and hydration tests show that the FR performs well in high TDS waters, even at low temperature, reaching its peak performance rapidly. The cationic FR possesses high mechanical stability even after being exposed to high pumping rates in the friction loop. It is well known that cationic FRs are not compatible with polyanionic scale inhibitors; in this study, a compatible scale inhibitor, SI-1, is identified. Additionally, there has historically been hesitation to use such cationic materials due to concerns of formation compatibility with negatively charged source rocks or flocculation in water treatment plants. Thermal testing with cationic FRs reveals that the material degrades to anionic without the aid of any other additive, which is confirmed by the fact that addition of polycationic additive, C1, caused coacervation in the heat-treated sample. As a result, concerns over effects of rock wettability or incompatibility with water treatment additives can be alleviated. No anionic FRs undergo similar change of the ionic charge. Thermal testing with cationic FR solutions also shows a significant viscosity drop, surprisingly without pronounced molecular weight loss (via MALLS). However, core flow testing of cationic FR fluids shows good regained permeability, even without breakers, further confirming self-cleaning capability. The degradation mechanism of these FRs will be shown. The self-cleaning capability of the dry cationic FR, even at relatively low bottomhole temperature (BHT), in combination with its high salt-tolerance, makes it an excellent friction reducer for multiple applications, especially with low quality water.

Self-Cleaning Characteristics of Mesoporous Nano-Crystalline TiO2-SiO2 Thin Films

2018 ◽  
Author(s):  
Chen Chen ◽  
Xinguo Ma ◽  
Shijie Dong ◽  
Xiaobo Chen ◽  
Chuyun Huang
Keyword(s):  
Contact Angle ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Surface Morphology ◽  
Ultraviolet Light ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Hydroxyl Groups ◽  
Self Cleaning ◽  
Short Time

Since titanium dioxide was found to exhibit super-hydrophilicity under ultraviolet light, researches on titanium dioxide self-cleaning films have also been continuing. It has been proved that mesoporous structure of the film can improve its optical transmittance, reduce the light reflection, and improve the utilization of light, thus enhancing its photocatalytic activity. The doping of SiO2 in TiO2 can increase the number of hydroxyl groups on the surface of the film, inhibit the transformation of TiO2 crystals and increase the specific surface area, thus improving its photocatalytic activity and reduce the contact angle of water droplets, and eventually enhancing the self-cleaning effect of the film. In this paper, the effects of different volume fractions of SiO2 on the surface morphology, mechanical stability, wettability and photocatalytic activity of TiO2 films are explored in great detail. It has been found that the film shows a smooth, crack-free surface morphology at a volume fraction of 20% SiO2. After exposure to ultraviolet light, a contact angle of 0.75° can be obtained in a short time, and the film exhibits super-hydrophilicity. Moreover, a low contact angle is maintained for a long time after the lighting is stopped. Methyl orange is adopted to evaluate its photocatalytic performance. Under ultraviolet light, it can be almost completely degraded in a short time, showing great photocatalytic activity. All the mesoporous films prepared exhibit good optical permeability. At the same time, it has been found that the films prepared are of good adhesion and maintain acid and alkaline resistance under natural conditions.

scholarly journals Transparent Photocatalytic Thin Films on Flexible Polymer Substrates

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1945 ◽  
Author(s):  
Nives Vodišek ◽  
Andraž Šuligoj ◽  
Dorota Korte ◽  
Urška Lavrenčič Štangar
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Vinylidene Fluoride ◽  
Mechanical Stability ◽  
Light Exposure ◽  
Beam Deflection ◽  
Polymer Substrates ◽  
Flexible Polymer ◽  
Self Cleaning ◽  
Photocatalytic Films

Self-cleaning and/or photocatalytic films on polymer substrates have found numerous applications during the past decades. However, the common demand for high-temperature post synthesis treatment limits the application to temperature resistant substrates only. Herein, we prepared self-cleaning photocatalytic films on four thermosensitive polymeric substrates: polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), and acryl coated polyester (PES) fabric (D2) with poly(vinylidene fluoride) (PVDF) containing lacquer (D1). TiO2 was prepared via a low-temperature sol-gel process using titanium(IV) isopropoxide and zirconium(IV) butoxide as precursors with various loading levels of Zr; 0, 5, 10, and 20 mol.%, and deposited on the substrates by using a SiO2 binder in form of thin films (ca. 200 nm thick) via dip-coating. The films were characterized by SEM, hardness test, UV-Vis, photothermal beam deflection spectroscopy, and IR spectroscopy, while photocatalytic activity was measured by the fluorescence-based method of the terephthalic acid probe and wetting by contact angle measurements. Films containing 10 mol.% of Zr showed the best compromise regarding photocatalytic activity and mechanical stability while from substrates point of view PVC performed the best, followed by PMMA, D1, and D2. The beneficial role of SiO2 binder was not only guaranteeing excellent mechanical stability, but also to prevent the D1 polymer from deterioration; the latter was found to be labile to long-term solar-light exposure due to degradation of the top PVDF layer.

scholarly journals Development and Biocompatibility Evaluation of Photocatalytic TiO2/Reduced Graphene Oxide-Based Nanoparticles Designed for Self-Cleaning Purposes

Nanomaterials ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 279 ◽  
Author(s):  
Ionela Nica ◽  
Miruna Stan ◽  
Marcela Popa ◽  
Mariana Chifiriuc ◽  
Gratiela Pircalabioru ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Self Cleaning ◽  
Photocatalytic Tio2
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