The aim of this research is the study of self-cleaning and antibacterial activity of
SiO
2
/TiO
2
thinfilm contains copper in it on ordinary ceramic tiles substrates. Four solutions using the sol-gel ...method with various volume ratio of Si/Ti precursors (i.e., 1/9, 2/8, 3/7, and 4/6) were prepared. Then, they were deposited on the ceramic tiles via the dip-coating technique and heated through thermal treatment at 650° for an hour. The XRD results show anatase and rutile structures are the main phases in the composite films of Cu
/SiO
2
/TiO
2
coatings. The rms roughness obtained by AFM for ceramic tile was initially ~20 nm, which reduced to <2 nm after deposition. The SEM images, depicted a uniform and crack-free thin-film coating with a thickness <30 nm. Stearic acid coating was applied on the samples as a pollution and was completely removed after being subjected to 24 hrs of UV illumination (400–800 μW/
cm
2
) in an environment with low and variable humidity (21–37 RH). About 76° reduction of water contact angle (WCA) was observed during photocatalytic test for the 1/9 (optimum) sample. In addition, a 33° decrease in WCA was measured in the light-induced hydrophilicity experiment. The 1/9 sample that reacted mostly under UV illumination in both photocatalytic and light-induced hydrophilicity was concluded as the optimum one. To improve the antibacterial property of the coating, copper nitrate trihydrate was added to the 1/9 solution. Moreover, antibacterial test was performed through “viable cell count” method by E. coli bacteria. The results of antibacterial test showed a 99% and 99.99% reduction in the number of E. coli bacteria during 1 and 24 hrs intervals, respectively. This is, surprisingly, to the best of our knowledge, the same as the results that can be obtained using silver nanoparticles.
Graphical abstract
Highlights
Self-cleaning take place before 24 hours under a very weak UV illumination.
Elimination of 99% and 99.99% of E. coli bacteria within 1 and 24 hours of using Cu instead of Ag.
Self-clean and antibacterial thin-film coating which is commercially affordable rather than using detergent materials.
No visible changes have been observed in the design or color of ceramic tiles.
Applicable to use in different environments with variable climate conditions.
•Thin layers of anatase titanium dioxide were coated on glass by spray pyrolysis method.•The layers were hydrogenated by DC plasma from room temperature up to 350°C.•Band gap of the layers was ...decreased 0.13eV by plasma treatment at highest temperature.•There is a specific plasma temperature range, which hydrophilicity and photocatalytic properties of the layers are optimum.
Thin layers of anatase titanium dioxide were coated on glass by spray pyrolysis method. The layers were hydrogenated by DC plasma from room temperature up to 350°C. Hydrogen plasma treatment at low temperatures, leads to decrease the surface roughness, while surface roughness is increased by enhancing plasma temperature. Layers’ band gap was decreased 0.13eV by plasma treatment at highest temperature. Hydrophilicity and photocatalytic properties of the layers under plasma treatment at 150 and 200°C, were improved noticeably. However, plasma treatment at temperatures above 200°C was lead to decrease hydrophilicity and photocatalytic activity of TiO2 layers. The reason seems formation of oxygen vacancies in the interior layers that act as charge carriers’ recombination centers.
Elastic and thermal properties of the TiO(2) lattice in anatase and rutile phases were studied in the framework of density functional perturbation theory within the local density approximation (LDA) ...and generalized-gradient approximation (GGA). The full elastic constant tensors of the polymorphs were calculated by linear fits to the acoustic branches of the phonon band structure near the center of the first Brillouin zone in symmetry directions of the crystals. It was observed that the elastic constants within the GGA are in better agreement with experiment. In addition, the Born effective charges, dielectric tensor, heat capacity, mean sound velocity and Debye temperature were calculated. The heat capacity at room temperature and the Debye temperature within the LDA are in better agreement with the experimental results. Therefore, using the phonon band structure and the density of states, one can obtain the important mechanical and thermal properties of materials.
In present work, hydrophobic copper(I) oxide (Cu
2
O) surfaces were fabricated by chemical bath deposition method. Copper oxide layers on glass slides were coated using copper sulfate as a precursor. ...To examine wetting properties of copper oxide surfaces, various samples were prepared at different numbers of coating cycles and sintering conditions (temperature, time, and atmosphere). Morphology, composition, and optical absorption of the copper oxide layers were characterized by profilometer, AFM, XRD, UV–Vis photospectroscopy, and water contact angle measurements. It was observed that hydrophobicity decreases by increasing oxygen amount of the sintering atmosphere. In fact, this is the result of an increase in the surface oxygen amount and consequently the increase of surface energy. An optimum thickness and surface morphology is obtained for hydrophobicity of these thin films which are due to air trapping at more narrow valleys and development of the Cassie–Baxter phase. Moreover, the effects of valley’s height and width on the wetting were investigated. It is shown that the width of the valleys is a more important factor in developing the Cassie–Baxter phase than the height of valleys. Furthermore, the obtained results show that all copper(І) oxide surfaces tend to a hydrophobicity behavior after 1 week drying at ambient conditions. The measured water contact angles of Cu
2
O layers were as high as 112°, without sintering or fatty acid modification. Nevertheless, it was enhanced up to 134° at the optimum sintering condition under nitrogen atmosphere. To the best of our knowledge, this is the first precisely study on wettability of Cu
2
O thin films prepared by this method at the various preparation conditions.
•In this work we have investigated the effect of fourteen important properties in superconductivity on the elements of periodic table and reported these features as priority in order.•Then, one of ...the most important factors in superconductivity, i.e. electron-phonon coupling constant is investigated using machine learning algorithm.•In this model, Debye and transition temperatures are as descriptors and the target value, electron-phonon coupling constant is predicted for 28 elements via cross-validation technique.•Our predicted electron-phonon coupling constants results are in accordance with the available values by 88% accuracy.
Finding new properties of materials by machine learning is an active branch in materials research. Among the various materials groups, superconductivity is not well known despite numerous studies. In this work we have investigated the effect of fourteen important properties in superconductivity on the elements of periodic table and reported these features as priority in order. Then, one of the most important factors in superconductivity, i.e. electron-phonon coupling constant is investigated using machine learning algorithm. In this model, Debye and transition temperatures are as descriptors and the target value, electron-phonon coupling constant is predicted for 28 elements via cross-validation technique. Our predicted electron-phonon coupling constants results are in accordance with the available values by 88% accuracy. So, we are able to build up a model to predict the unavailable electron-phonon coupling constant of elements.
Nanosized TiO
2 thin films with anatase structure were synthesized by a sol–gel dip coating method using TiCl
4-ethanol solution as a precursor. The resulting solution was aged between 0 up to 24
h ...and characterized by the X-ray diffraction, atomic force microscopy (AFM), and UV–vis photospectroscopy. The AFM reveals that aging time incites the grain growth of crystal in the TiO
2 films. The effect of aging time on morphology, photocatalytic, and superhydrophilic behavior of the films was also studied. It was found that there is an optimum aging time that photocatalytic and superhydrophilic yields reach a maximum, simultaneously. Photocatalytic and photo-wettability mechanisms follow two kinds of behaviors, depending on whether the aging time is less or more than a threshold value of around 1
h.
► Anatase TiO2 nano thin films were prepared on glass substrates by sol–gel dip coating method using Tween 80 as a surfactant, TiCl4 as the Ti precursor, and ethanol as a solvent. ► Aging time ...effects of the sol preparation on the morphology, photocatalytic, and superhydrophilicity behaviors of the films were studied. ► It was seen that there is an aging time which photocatalytic and superhydrophilicity characters are maximum, simultaneously.
Anatase TiO2 nano thin films were prepared on glass substrates by sol–gel dip coating method using Tween-80 as a surfactant, TiCl4 as the Ti precursor, and ethanol as a solvent. Atomic force microscopy, X-ray diffraction, and UV–Vis. photospectrometery experiments were performed to analyze the surface, structural and optical characteristics of the films. The effects of chemical aging time on the morphology, photocatalytic and superhydrophilicity behaviors of the films were studied. We show there is an optimum aging time at 2h which photocatalytic and superhydrophilicity properties are at their maximum values simultaneously. This is useful in the self-cleaning industry.
Pure TiO2 and nitrogen doped titanium dioxide (N-TiO2) thin films were prepared by sol-gel method through spin coating on soda lime glass substrates. TiCl4 and urea were used as Ti and N sources in ...the sol. XRD results showed nitrogen doping has retarded anatase to rutile phase transformation. The doping also leads to a decrease in roughness of the samples from 4nm (TiO2) to 1nm (N-TiO2). However, surface analysis by statistical methods reveals that both surfaces have self-affine structure. Optical band gap of thin films was shifted from 3.65eV (TiO2) to 3.47eV (N-TiO2). Hydrophilic conversion and photocatalytic degradation properties of thin films were investigated and exhibited that N-TiO2 thin film has more preferable hydrophilicity and photocatalytic properties under UV illumination.
▶ The influences of three different aging times on crystallinity, photocatalytic, and superhydrophilicity behaviors of the anatase TiO2 thin films were investigated. ▶ In one of the samples, ...photocatalytic and superhydrophilic phenomena reach optimum, simultaneously. ▶ This is very useful for self-cleaning application.
Anatase TiO2 thin films were prepared on glass substrates by the sol–gel dip coating method with TiCl4 as the Ti precursor and Tween 80 as a surfactant. XRD, AFM, and UV–Vis photospectroscopy experiments were used to analyze the structural and optical characteristics of the films. The influences of three different aging times on crystallinity, morphology, photocatalytic, superhydrophilicity behaviors, and size of the obtained TiO2 grains were investigated. With increasing the aging time, crystallite size of anatase structure and thickness of the films were increased. It was shown that in one of the samples, photocatalytic and superhydrophilic phenomena reach optimum, simultaneously. This could be very useful for self-cleaning application.
Copper based layers were fabricated on gold/silicon (100) substrates by using square pulse electrodeposition at different deposition temperatures. The predominant crystalline plane on Cu2O samples at ...temperatures higher than 30 °C is (111), which is the most hydrophobic facet of Cu2O cubic structure. Different crystallite structures such as semivertical leaves, fractal trees, and octahedral pyramids were formed on the surface. These water‐repellent samples have hierarchical structures, including octahedral pyramid microstructures with small spherical balls on them and well‐branched micrometric vertical leaves on the surface. They provide a suitable surface for trapping air pockets inside the structure and increasing the water contact angle up to 154°. This approach may be applicable to the large‐scale preparation of water‐repellent surfaces as superhydrophobicity can be achieved in a one‐step deposition process without any secondary modifications.
Superhydrophobic hierarchical copper‐based surfaces: Different surface structures, including octahedral pyramids, dendrite leaves, and hierarchical structures were fabricated by using pulsed potential electrodeposition at various bath temperatures. Increasing the bath temperature has a big impact on the complexity of the surface structures as well as roughness, as the extra thermal energy increases the deposition rate. These structures provide a suitable surface for trapping air pockets and increasing the water contact angle up to 154°.
