scholarly journals Preparation of Water Repellent Layer on Glass Using Hydrophobic Compound Modified Rice Hull Ash Silica

2018 ◽  
Vol 18 (4) ◽  
pp. 587 ◽  
Author(s):  
Alfa Akustia Widati ◽  
Nuryono Nuryono ◽  
Dessy Puspa Aryanti ◽  
Madjid Arie Wibowo ◽  
Eko Sri Kunarti ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sio2 Layer ◽  
Rice Hull ◽  
Water Repellent ◽  
Layer By Layer ◽  
Ambient Conditions ◽  
Rice Hull Ash ◽  
Water Contact ◽  
Layer Number

In this study water repellent layered glass has been prepared by coating silica (SiO2) combined with a hydrophobic silane compound. SiO2 was extracted from rice hull ash and two silane compounds, namely hexadecyltrimethoxysilane (HDTMS) and trimethylchlorosilane (TMCS) were used. Coating was performed through two deposition techniques, i.e. one step (mono-layer) and layer by layer (LBL, multi-layer). The effect of silane to SiO2 mole ratio, silane type and layer number on the glass characters was evaluated. Characterization included hydrophobicity, transparency, surface roughness and stability of coating. Results showed that increasing the mole ratio of silane to SiO2 and the layer number increased the hydrophobicity of the glass surface. The optimum mole ratio was 5:1 and the significant increase of contact angle occurred at lower mole ratio, but the stability tends to be increased at higher mole ratio. For HDTMS-SiO2 layer, the technique of LBL technique produced a coating with higher hydrophobicity and transparency than single-stage one. The LBL technique produced the highest water contact angle of 103.7° with transmittance of 96%, while for TMCS-SiO2 layer the one stage technique produced hydrophobic layer with higher water contact angle of 108.0° and transparency about 94.52%. The prepared hydrophobic glasses were relatively stable in polar and non-polar solvents, but unstable to ambient conditions.

Fast and simple fabrication of SiO2/poly(vinylidene fluoride) coated cotton fabrics with asymmetric wettability via a facile spray-coating route

2018 ◽  
Vol 89 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
Rongrong Yu ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
Jianhua Ran ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Vinylidene Fluoride ◽  
Spray Coating ◽  
Cotton Fabrics ◽  
Water Repellent ◽  
Water Contact ◽  
Repellent Property ◽  
Poly Vinylidene Fluoride

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.

scholarly journals Superhydrophobic organosilicon-based coating system by a novel ultravoilet-curable method

2017 ◽  
Vol 7 ◽  
pp. 184798041770279 ◽  
Author(s):  
Baojiang Liu ◽  
Taizhou Tian ◽  
Jinlong Yao ◽  
Changgen Huang ◽  
Wenjun Tang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Silica Nanoparticles ◽  
Water Contact Angle ◽  
Cotton Fabric ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Water Repellent ◽  
Step Method ◽  
Water Contact

A robust superhydrophobic organosilica sol-gel-based coating on a cotton fabric substrate was successfully fabricated via a cost-effective one-step method. The coating was prepared by modification of silica nanoparticles with siloxane having long alkyl chain that allow to reduce surface energy. The coating on cotton fabric exhibited water contact angle of 151.6°. The surface morphology was evaluated by scanning electron microscopy, and surface chemical composition was measured with X-ray photoelectron spectroscopy. Results showed the enhanced superhydrophobicity that was attributed to the synergistic effect of roughness created by the random distribution of silica nanoparticles and the low surface energy imparted of long-chain alkane siloxane. In addition, the coating also showed excellent durability against washing treatments. Even after washed for 30 times, the specimen still had a water contact angle of 130°, indicating an obvious water-repellent property. With this outstanding property, the robust superhydrophobic coating exhibited a prospective application in textiles and plastics.

scholarly journals Fabrication of Electrospun Membranes based on Poly(caprolactone) (PCL) and PCL/Chitosan Layer by Layer for Tissue Engineering

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Choi Yee Foong ◽  
Naznin Sultana
Keyword(s):  
Tissue Engineering ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Water Uptake ◽  
Solution Concentration ◽  
Layered Composite ◽  
Layer By Layer ◽  
Electrospun Membrane ◽  
Water Contact ◽  
Electrospun Membranes

Recently, in the field of tissue engineering, fabrication of three-dimensional (3D) electrospun scaffold or membrane is much emphasized. In this study, layered composite scaffolds or membranes were fabricated using two biodegradable polymers, polycaprolactone (PCL) and Chitosan layer-by-layer with multilayer electrospinning method. Characterizations of membranes were done using several techniques. Electrospun composite membrane’s surface morphology was examined using a Scanning Electron Microscopy (SEM) and the wettability of the material’s surface was determined using water contact angle measuring measurement (WCA). Water uptake properties of electrospun membrane were also determined. Using optimized solution concentration and electrospinning processing parameters, the composite PCL/Chitosan and PCL layer-by-layer were successfully fabricated. It was observed from SEM that the composite electrospun membranes produced consisted microfibers and nanofibers within single scaffold. The water contact angle for the double-layered composite electrospun membranes was lower than the pure PCL. The double-layered composite membrane also had higher water uptake properties compared to pure PCL scaffold.

scholarly journals Ultrahydrophobic Textiles Using Nanoparticles: Lotus Approach

2008 ◽  
Vol 3 (4) ◽  
pp. 155892500800300 ◽  
Author(s):  
Karthik Ramaratnam ◽  
Swaminatha K. Iyer ◽  
Mark K. Kinnan ◽  
George Chumanov ◽  
Phillip J. Brown ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Contact Angle Hysteresis ◽  
Water Repellency ◽  
Textile Material ◽  
Water Repellent ◽  
Complete Wetting ◽  
Water Contact ◽  
Lotus Effect ◽  
Textile Materials

It is well established that the water wettability of materials is governed by both the chemical composition and the geometrical microstructure of the surface.1 Traditional textile wet processing treatments do indeed rely fundamentally upon complete wetting out of a textile structure to achieve satisfactory performance.2 However, the complexities introduced through the heterogeneous nature of the fiber surfaces, the nature of the fiber composition and the actual construction of the textile material create difficulties in attempting to predict the exact wettability of a particular textile material. For many applications the ability of a finished fabric to exhibit water repellency (in other words low wettability) is essential2 and potential applications of highly water repellent textile materials include rainwear, upholstery, protective clothing, sportswear, and automobile interior fabrics. Recent research indicates that such applications may benefit from a new generation of water repellent materials that make use of the “lotus effect” to provide ultrahydrophobic textile materials.3,4 Ultrahydrophobic surfaces are typically termed as the surfaces that show a water contact angle greater than 150°C with very low contact angle hysteresis.4 In the case of textile materials, the level of hydrophobicity is often determined by measuring the static water contact angle only, since it is difficult to measure the contact angle hysteresis on a textile fabric because of the high levels of roughness inherent in textile structures.

scholarly journals Strength and Water-Repelling Properties of Cement Mortar Mixed with Water Repellents

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5407
Author(s):  
Hyeju Kang ◽  
Sukpyo Kang ◽  
Byoungky Lee
Keyword(s):  
Contact Angle ◽  
Compressive Strength ◽  
Water Contact Angle ◽  
Cement Mortar ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Rapid Hardening ◽  
Before And After ◽  
Large Water

In this study, the compressive strength and water contact angle of mortar specimens prepared by mixing two types of water repellent with ordinary Portland cement (OPC) and rapid-hardening cement mortar were measured before and after surface abrasion. In addition, the hydration products and chemical bonding of cement mortar with the repellents were examined using X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the performance of these cement mortar mixtures as repair materials. We found that the fast-hardening cement mortar mixture containing the oligomer water repellent showed the best performance with a high compressive strength and large water contact angle. With the oligomer water repellent, the rapid-hardening cement mortar mixture showed contact angles of 131° and 126° even after a 2 mm abrasion, thereby confirming that the water repellent secured hydrophobicity through strong bonding with the entire cement mortar as well as its surface. The compressive strengths were found to be 34.5 MPa at 3 h and 54.8 MPa at 28 days, confirming that hydration occurred well despite the addition of water repellent.

scholarly journals WATER REPELLENT BREATHABLE PET/WOOL FABRIC VIA PLASMA POLYMERISATION TECHNOLOGY

2021 ◽  
Vol 2021 ◽  
pp. 74-80
Author(s):  
A. Haji ◽  
M. Khajeh Mehrizi ◽  
M. Ali Tavanai ◽  
M. Gohari
Keyword(s):  
Contact Angle ◽  
Tensile Strength ◽  
Water Contact Angle ◽  
Air Permeability ◽  
Water Repellent ◽  
Wool Fabric ◽  
Water Contact ◽  
Hydrophobic Polymers ◽  
Treated Sample ◽  
Bending Length

Water-repellent textiles are usually prepared by application of hydrophobic polymers such as fluorocarbons on fabrics using padding or spraying methods followed by drying and curing steps. These procedures impart hydrophobicity to the fabric, but harm the physical and handle properties of the fabric. In this study, low-pressure plasma was employed for the polymerization of 1H,1H,2H,2H-Perfluorooctyl acrylate on PET/Wool fabric for obtaining water-repellent properties with minimum effect on other desirable properties. To compare the results with the conventional industrial processes, a sample was treated with a commercial water-repellent agent using pad-dry-cure method. The water contact angle, bending length, tensile strength, air permeability, and surface morphology of the samples were compared. The plasma-treated sample showed similar water contact angle and higher fastness properties compared with the sample prepared by the conventional method. The tensile strength of the samples was similar, while the air permeability of the plasmatreated sample was higher and the coating was more uniform compared with the sample prepared by the paddry- cure method.

scholarly journals What Is the Value of Water Contact Angle on Silicon?

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1554 ◽  
Author(s):  
Paweł Bryk ◽  
Emil Korczeniewski ◽  
Grzegorz S. Szymański ◽  
Piotr Kowalczyk ◽  
Konrad Terpiłowski ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Md Simulations ◽  
Surface Cleaning ◽  
Sio2 Layer ◽  
Water Contact ◽  
Pure Silicon ◽  
Wetting Properties ◽  
Cleaning Methods

Silicon is a widely applied material and the wetting of silicon surface is an important phenomenon. However, contradictions in the literature appear considering the value of the water contact angle (WCA). The purpose of this study is to present a holistic experimental and theoretical approach to the WCA determination. To do this, we checked the chemical composition of the silicon (1,0,0) surface by using the X-ray photoelectron spectroscopy (XPS) method, and next this surface was purified using different cleaning methods. As it was proved that airborne hydrocarbons change a solid wetting properties the WCA values were measured in hydrocarbons atmosphere. Next, molecular dynamics (MD) simulations were performed to determine the mechanism of wetting in this atmosphere and to propose the force field parameters for silica wetting simulation. It is concluded that the best method of surface cleaning is the solvent-reinforced de Gennes method, and the WCA value of silicon covered by SiO2 layer is equal to 20.7° (at room temperature). MD simulation results show that the mechanism of pure silicon wetting is similar to that reported for graphene, and the mechanism of silicon covered by SiO2 layer wetting is similar to this observed recently for a MOF.

Recent advances in corrosion resistant superhydrophobic coatings

2018 ◽  
Vol 36 (2) ◽  
pp. 127-153 ◽  
Author(s):  
Ahmed Bahgat Radwan ◽  
Aboubakr M. Abdullah ◽  
Nasser A. Alnuaimi
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Metals And Alloys ◽  
Superhydrophobic Surfaces ◽  
Water Repellent ◽  
Water Contact ◽  
Corrosion Resistant ◽  
Superhydrophobic Coatings ◽  
Recent Advances

AbstractExtreme water-repellent (superhydrophobic) coatings with water contact angle higher than 150° have caught the attention of corrosion researchers in the last decade as they can be used to protect metals and alloys against corrosion. The latter is a serious problem, as it can threaten human lives in addition to its deleterious effects on the economy and environment. Superhydrophobic coatings (SHCs) can be achieved by lowering the surface energy of a certain coating through combining some of its surface features at the microscale and nanoscales. Although SHCs can be prepared using many different easy techniques, none, to the best of our knowledge, has been applied, so far, on an industrial scale for protection against corrosion of metals and alloys. The present work explains the different models of superhydrophobic surfaces (SHSs) and reviews their fabrication and processing methods with a focus on the recent advances in the corrosion protection of the SHC.

scholarly journals Design of SiO2/TiO2 that Synergistically Increases The Hydrophobicity of Methyltrimethoxysilane Coated Glass

2019 ◽  
Vol 17 (1) ◽  
pp. 798-805 ◽  
Author(s):  
Alfa Akustia Widati ◽  
Nuryono Nuryono ◽  
Indriana Kartini
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Research Work ◽  
Dip Coating ◽  
Layer By Layer ◽  
Titanium Tetraisopropoxide ◽  
Water Contact ◽  
Nanoscale Structures ◽  
Coated Glass

AbstractThis research work presents the design of a mixture of SiO2/TiO2 that increases the surface roughness and hydrophobicity of methyltrimethoxysilane (MTMS) coated glass. The deposition of SiO2, TiO2, and MTMS were conducted using a layer by layer dip coating technique. The SiO2/TiO2 coating was derived from complete hydrolysis of tetraethylorthsilicate and titanium tetraisopropoxide. In order to evaluate and compare the performance of SiO2/TiO2/MTMS coated glass, the SiO2/SiO2/MTMS and TiO2/TiO2/MTMS were also fabricated. SiO2/TiO2/MTMS samples displayed the highest water contact angle. The topography of surfaces showed that SiO2/TiO2/MTMS exposed higher surface roughness with micro-nanoscale structures. The sequence of SiO2 and TiO2 influenced the water contact angle and the stability of the coatings. SiO2/TiO2/MTMS produced higher contact angle and stability than TiO2/SiO2/MTMS.

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