scholarly journals Superhydrophobic Coatings Based on Siloxane Resin and Calcium Hydroxide Nanoparticles for Marble Protection

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 334 ◽  
Author(s):  
Aikaterini Chatzigrigoriou ◽  
Ioannis Karapanagiotis ◽  
Ioannis Poulios
Keyword(s):  
Electron Microscopy ◽  
Calcium Hydroxide ◽  
Composite Coatings ◽  
Exchange Process ◽  
Sio2 Nanoparticles ◽  
Contact Angles ◽  
Water Repellent ◽  
Aqueous Emulsion ◽  
Aesthetic Appearance ◽  
Static Contact

Calcium hydroxide (Ca(OH2)) nanoparticles are produced following an easy, ion exchange process. The produced nanoparticles are characterized using transmission electron microscopy (TEM) and Fourier- transform infrared spectroscopy (FTIR) and are then dispersed in an aqueous emulsion of silanes/siloxanes. The dispersions are sprayed on marble and the surface structures of the deposited coatings are revealed using scanning electron microscopy (SEM). By adjusting the nanoparticle concentration, the coated marble obtains superhydrophobic and water repellent properties, as evidenced by the high static contact angles of water drops (> 150°) and the low sliding angles (< 10°). Because Ca(OH)2 is chemically compatible with limestone-like rocks, which are the most common stones found in buildings and objects of the cultural heritage, the produced composite coatings have the potential to be used for conservation purposes. For comparison, the wetting properties of another superhydrophobic and water repellent coating composed of the same siloxane material and silica (SiO2) nanoparticles, which were commonly used in several previously published reports, were investigated. The suggested siloxane+Ca(OH)2 composite coating offers good protection against water penetration by capillarity and has a small effect on the aesthetic appearance of marble, according to colorimetric measurements.

scholarly journals Facile Method to Prepare Superhydrophobic and Water Repellent Cellulosic Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ioannis Karapanagiotis ◽  
Diana Grosu ◽  
Dimitra Aslanidou ◽  
Katerina E. Aifantis
Keyword(s):  
Particle Concentration ◽  
Water Repellency ◽  
Contact Angles ◽  
Water Repellent ◽  
Tissue Paper ◽  
Nanoparticle Films ◽  
High Particle ◽  
Aesthetic Appearance ◽  
Static Contact ◽  
Wide Range

Silica nanoparticles (7 nm) were dispersed in solutions of a silane/siloxane mixture. The dispersions were applied, by brush, on four types of paper: (i) modern, unprinted (blank) paper, (ii) modern paper where a text was printed using a common laser jet printer, (iii) a handmade paper sheet detached from an old book, and (iv) Japanese tissue paper. It is shown that superhydrophobicity and water repellency were achieved on the surface of the deposited films, when high particle concentrations were used (≥1% w/v), corresponding to high static (θS≈ 162°) and low tilt (θt< 3°) contact angles. To interpret these results, scanning electron microscopy (SEM) was employed to observe the surface morphologies of the siloxane-nanoparticle films. Static contact angles, measured on surfaces that were prepared from dilute dispersions (particle concentration <1% w/v), increased with particle concentration and attained a maximum value (162°) which corresponds to superhydrophobicity. Increasing further the particle concentration did not have any effect onθS. Colourimetric measurements showed that the superhydrophobic films had negligible effects on the aesthetic appearance of the treated papers. Furthermore, it is shown that the superhydrophobic character of the siloxane-nanoparticle films was stable over a wide range of pH.

Fabrication of reinforced hydrophobic coatings for the protection of silk fabric

2019 ◽  
Vol 89 (18) ◽  
pp. 3811-3824
Author(s):  
Suhua Zhao ◽  
Ru He ◽  
Xin Zhang ◽  
Weichen Zeng ◽  
Tianyi Zhang ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Composite Coatings ◽  
Contact Angles ◽  
Diglycidyl Ether ◽  
Water Soluble ◽  
Silk Fabric ◽  
Hydrophobic Property ◽  
Point Distribution ◽  
Silica Composite ◽  
Static Contact

The design of water-resistance and breathable materials applied to the protection of a historical silk textile has raised considerable interest for their highly practical potential. Thus, simple and functional composite coatings have been investigated and applied on Bombyx mori silk fabrics by spraying silk fibroin and a water soluble siloxane emulsion enriched with silica nanoparticles (12 nm). The layer of spraying silk fibroin on the surface of the silk fabric resulted in mesoscopic molecular network reconstruction by hydrogen bonds and crosslinking of ethylene glycol diglycidyl ether to improve the physical property of the silk fabric. By systematically investigating silica composite treatment, it was found that the sample treated with silica composite coatings possessed a good hydrophobic property, in which the static contact angles increased from 43.27° to 145.77° for uncoated and coated samples, respectively. As determined by Fourier transform-infrared spectroscopy analyses, hydrophobic components such as Si-O-Si, Si-O were successfully attached to the silk fabric. The scanning electron microscopy images and the energy-dispersive X-ray spectroscopy map point distribution images showed that the coating of the silica composite forms a uniform nano-scale structure, which improved the waterproof and breathable performance. Compared with uncoated fabric, the silica composite treatment was endowed with enhanced air permeability of 446.47 mm/s. After the abrasion and washing cycles, high durability of the coated fabric was demonstrated. Excellent hydrophobic capability could help silk fabric avoid the destruction of any harmful pollutant, such as light, bacteria, sewage and so on. Furthermore, the proposed relationship between the adhesive structure and the waterproof/breathable property is applicable in the design of functional silk textiles with different levels for protective performance.

scholarly journals Surface Properties of Spray-Assisted Layer-By-Layer ElectroStatic Self-Assembly Treated Wooden Take-Off Board

2021 ◽  
Vol 11 (2) ◽  
pp. 836
Author(s):  
Yi Wan ◽  
Sijie Hou ◽  
Mengyao Guo ◽  
Yanchun Fu
Keyword(s):  
Self Assembly ◽  
Treated Wood ◽  
Contact Angles ◽  
Water Repellent ◽  
Layer By Layer ◽  
Air Exposure ◽  
Limiting Oxygen Index ◽  
Sodium Phytate ◽  
Static Contact ◽  
Combustion Tests

Wooden take-off board is easy to crack, deform, discolor, and decay when it is used outdoors, which not only increases maintenance costs but also reduces its service life. Multifunctional coatings with UV-resistant, water-repellent, and flame-retardant properties were successfully obtained on the surface of a wooden take-off board substrate by spray-assisted layer-by-layer self-assembly. The coatings consisted of positively-charged chitosan, Al (OH)3, and negatively-charged sodium phytate through electrostatic adsorption several times. The treated wood exhibited high UV resistance, and the color remained constant after 720 hours of ultraviolet irradiation. The wettability of the wood surface after treatment became superhydrophobic, with initial static contact angles as high as 140°. In addition, limiting oxygen index and air exposure combustion tests were used to verify that chitosan, sodium phytate, and aluminum hydroxide could synergistically confer significant fire resistance to modified wood.

scholarly journals Non-fluorine surface modification of acetylated birch for improved water repellence

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Haiyan Yin ◽  
Maziar Sedighi Moghaddam ◽  
Mikko Tuominen ◽  
Andra Dėdinaitė ◽  
Magnus Wålinder ◽  
...  
Keyword(s):  
Surface Modification ◽  
Color Change ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Aesthetic Appearance ◽  
The Aesthetic ◽  
Surface Modified ◽  
Wilhelmy Plate Method ◽  
Fluorinated Surface

Abstract In this work, a non-fluorinated surface treatment, i.e., hydrophobized silicone nanofilaments, was applied on both birch and acetylated birch wood samples via a gas-phase based reaction. A superhydrophobic behavior was observed on both the surface-modified samples as revealed by the static water contact angles (CAs) greater than 160°, also valid for samples prepared with the shortest reaction time of 1 h. The dynamic wettability behavior of the samples was studied by a multicycle Wilhelmy plate method. The surface-modified acetylated birch exhibited a pronounced enhanced water resistance, resulting in very low water uptake of 3 ± 1 wt% after 100 cycles, which was not only about 29 and 5 times lower than that of the non-surface-modified birch and acetylated birch, respectively, but also three times lower than that of the surface-modified birch. Moreover, the aesthetic appearance of the acetylated wood was maintained as the surface modification only resulted in a small color change. This work shows the potential of preparing super water-repellent wood by non-fluorinated surface modification.

scholarly journals TEOS-Based Superhydrophobic Coating for the Protection of Stone-Built Cultural Heritage

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135
Author(s):  
Fotios G. Adamopoulos ◽  
Evangelia C. Vouvoudi ◽  
Eleni Pavlidou ◽  
Dimitris S. Achilias ◽  
Ioannis Karapanagiotis
Keyword(s):  
Cultural Heritage ◽  
Water Repellency ◽  
Contact Angles ◽  
Tetraethyl Orthosilicate ◽  
Superhydrophobic Coating ◽  
Water Penetration ◽  
Wetting Properties ◽  
Aesthetic Appearance ◽  
Static Contact ◽  
Water Drops

Tetraethyl orthosilicate (TEOS) is extensively used in the conservation of stone-built cultural heritage, which is often subjected to water-induced degradation processes. The goal of this study was to produce and study a TEOS-based material with the ability to repel liquid water. A sol solution of TEOS and 1H,1H,2H,2H-perfluorooctyl triethoxysilane (FAS) was prepared and deposited on marble. The static contact angles (CAs) of water drops on the coated marble surface were >170° and the sliding angles (SA) were <5°, suggesting that superhydrophobicity and water repellency were achieved on the surface of the synthesized TEOS-based coating. FTIR and SEM-EDS were employed to characterize the produced coating. The latter offered good protection against water penetration by capillarity, reducing the breathability of marble only by a small extent and with practically no effect on its aesthetic appearance. The durability of the coating was evaluated through various tests that provided very promising results. Finally, the versatility of the method was demonstrated as the TEOS-based coating was successfully deposited onto glass, brass, wood, silicon, paper and silk, which obtained extreme wetting properties.

scholarly journals Inexpensive and non-toxic water repellent coatings comprising SiO2 nanoparticles and long chain fatty acids

RSC Advances ◽  
2018 ◽  
Vol 8 (48) ◽  
pp. 27064-27072 ◽  
Author(s):  
Frances L. Heale ◽  
Kristopher Page ◽  
James S. Wixey ◽  
Philip Taylor ◽  
Ivan P. Parkin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Silica Nanoparticles ◽  
Sio2 Nanoparticles ◽  
Contact Angles ◽  
Water Repellent ◽  
Long Chain Fatty Acids ◽  
Water Contact ◽  
Hydrophobic Silica ◽  
Long Chain ◽  
Chain Fatty Acids

Special wettability durable coatings, with water contact angles exceeding 140°, have been fabricated using inexpensive and non-toxic functionalised hydrophobic-silica nanoparticles embedded in fatty acids.

Control of hydrophobic properties of polyester fabric coatings deposited with use of polytetrafluoroethylene telomers and silicon dioxide nanoparticles

2021 ◽  
Vol 22 (10) ◽  
pp. 447-457
Author(s):  
N. P. Prorokova ◽  
◽  
T. Yu. Kumeeva ◽  
I. V. Kholodkov ◽  
V. M. Bouznik ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Water Absorption ◽  
Sio2 Nanoparticles ◽  
Polyester Fabric ◽  
Contact Angles ◽  
Water Repellent ◽  
Silicon Dioxide Nanoparticles ◽  
Hydrophobic Properties ◽  
Additional Increase

The control possibility assessment of the water-repellent properties of polyester (PEF) fabric when its hydrophobizing with tetrafluoroethylene (TFE) telomers due to texturing by applying nanosized SiO2 is discussed. It was established that the use of a compound containing SiO2 nanoparticles and TFE telomers for hydrophobization of PEF fabrics led to an increase in roughness of the coatings, however, a decrease in contact angles of fabric and an increase in its water absorption were observed. This is due to an additional increase in hardness of the coating based on TFE telomers, when combined with SiO2 nanoparticles.

scholarly journals Effect of sizing agent on interfacial properties of carbon fiber-reinforced PMMA composite

2021 ◽  
Vol 30 ◽  
pp. 2633366X2097865
Author(s):  
Li Jian
Keyword(s):  
Shear Strength ◽  
Surface Treatment ◽  
Photoelectron Spectroscopy ◽  
Resin Composite ◽  
Contact Angles ◽  
Static Contact ◽  
Before And After ◽  
C Value ◽  
Interlayer Shear Strength ◽  
Pmma Resin

The surface treatment of carbon fibers (CFs) was carried out using a self-synthesized sizing agent. The effects of sizing agent on the surface of CFs and the interface properties of CF/polymethyl methacrylate (PMMA) composites were mainly studied. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and static contact angle were used to compare and study the CFs before and after the surface treatment, including surface morphology, surface chemical element composition, and wettability of the surface. The influence of sizing agent on the mechanical properties of CF/PMMA resin composite interface was investigated. The results show that after sizing treatment, the CF surface O/C value increased by 35.1% and the contact angles of CF and resin decreased by 16.2%. The interfacial shear strength and interlayer shear strength increased by 12.6%.

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

scholarly journals A Magnetic Nanocomposite Modifier for Improved Ultrasensitive Detection of Hexavalent Chromium in Water Samples

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 189
Author(s):  
Nuša Hojnik ◽  
Olivija Plohl ◽  
Matjaž Finšgar
Keyword(s):  
Electron Microscopy ◽  
Analytical Performance ◽  
Magnetic Nanocomposite ◽  
Ex Situ ◽  
Trace Determination ◽  
Silica Layer ◽  
X Ray ◽  
Square Wave ◽  
Static Contact

In this work, different electrodes were employed for the determination of Cr(VI) by the cathodic square‑wave voltammetry (SWV) technique and the square-wave adsorptive stripping voltammetry (SWAdSV) technique in combination with diethylenetriaminepentaacetic acid. Using SWV, a comparison of the analytical performance of the bare glassy carbon electrode (GCE), ex situ electrodes (antimony-film—SbFE, copper-film—CuFE, and bismuth-film—BiFE), and the GCE modified with a new magnetic nanocomposite (MNC) material was performed. First, the MNC material was synthesized, i.e., MNPs@SiO2@Lys, where MNPs stands for magnetic maghemite nanoparticles, coated with a thin amorphous silica (SiO2) layer, which was additionally functionalized with derived lysine (Lys). The crystal structure of the prepared MNCs was confirmed by X-ray powder diffraction (XRD), while the morphology and nano-size of the MNCs were investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), where TEM was additionally used to observe the MNP core and silica layer thickness. The presence of functional groups of the MNCs was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and surface analysis was performed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the modified electrodes was also tested by static contact angle measurements. Then, MNPs@SiO2@Lys was applied onto the electrodes and used with the SWV and SWAdSV techniques. All electrodes tested with the SWV technique were effective for Cr(VI) trace determination. On the other hand, the SWAdSV technique was required for ultra-trace determination of Cr(VI). Using the SWAdSV technique, it was shown that a combination of ex situ BiFE with the deposited MNPs@SiO2@Lys resulted in excellent analytical performance (LOQ = 0.1 µg/L, a linear concentration range of 0.2–2.0 µg/L, significantly higher sensitivity compared to the SWV technique, an RSD representing reproducibility of 9.0%, and an average recovery of 98.5%). The applicability of the latter system was also demonstrated for the analysis of a real sample.

Sign in / Sign up

Export Citation Format

Share Document