scholarly journals Fabrication of a Simultaneous Highly Transparent and Highly Hydrophobic Fibrous Films

2021 ◽  
Vol 11 (12) ◽  
pp. 5565
Author(s):  
Doo-Hyeb Youn ◽  
Kyu-Sung Lee ◽  
Sun-Kyu Jung ◽  
Mangu Kang
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Electrospun Fiber ◽  
Contact Angles ◽  
Light Transmittance ◽  
Electrospun Fibers ◽  
Water Contact ◽  
Aligned Fibers ◽  
Highly Hydrophobic

This paper discusses the fabrication and characterization of electrospun nanofiber scaffolds made of polystyrene (PS). The scaffolds were characterized in terms of their basis material molecular weight, fiber diameter distribution, contact angles, contact angle hysteresis, and transmittance. We propose an aligned electrospun fiber scaffold using an alignment tool (alignment jig) for the fabrication of highly hydrophobic (θW > 125°) and highly transparent (T > 80.0%) films. We fabricated the alignment jig to align the electrospun fibers parallel to each other. The correlation between the water contact angles and surface roughness of the aligned electrospun fibers was investigated. We found that the water contact angle increased as the surface roughness was increased. Therefore, the hydrophobic properties of the aligned electrospun fibers were enhanced by increasing the surface roughness. With the change in the electrospinning mode to produce aligned fibers rather than randomly distributed fibers, the transmittance of the aligned electrospun fibers increased. The increase in the porous area, leading to better light transmittance in comparison to randomly distributed light scattering through the aligned electrospun fibers increased with the fibers. Through the above investigation of electrospinning parameters, we obtained the simultaneous transparent (>80%) and hydrophobic (θW > 140°) electrospun fiber scaffold. The aligned electrospun fibers of PS had a maximum transmittance of 91.8% at the electrospinning time of 10 s. The water contact angle (WCA) of the aligned electrospun fibers increased from 77° to 141° as the deposition time increased from 10 s to 40 s. The aligned fibers deposited at 40 s showed highly hydrophobic characteristics (θW > 140°).

Addition of Cellulose Nanofibers to Control Surface Roughness for Hydrophobic Ceramic Coatings

2021 ◽  
Vol 21 (8) ◽  
pp. 4492-4497
Author(s):  
Eun Ae Shin ◽  
Gye Hyeon Kim ◽  
Jeyoung Jung ◽  
Sang Bong Lee ◽  
Chang Kee Lee
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Ceramic Coating ◽  
Cellulose Nanofibers ◽  
Ceramic Coatings ◽  
Coating Material ◽  
Textured Surface ◽  
Water Contact

Hydrophobic ceramic coatings are used for a variety of applications. Generally, hydrophobic coating surfaces are obtained by reducing the surface energy of the coating material or by forming a highly textured surface. Reducing the surface energy of the coating material requires additional costs and processing and changes the surface properties of the ceramic coating. In this study, we introduce a simple method to improve the hydrophobicity of ceramic coatings by implementing a textured surface without chemical modification of the surface. The ceramic coating solution was first prepared by adding cellulose nanofibers (CNFs) and then applied to a polypropylene (PP) substrate. The surface roughness increased as the amount of added CNFs increased, increasing the water contact angle of the surface. When the amount of CNFs added was corresponding to 10% of the solid content, the surface roughness average of the area was 43.8 μm. This is an increase of approximately 140% from 3.1 μm (the value of the surface roughness of the surface without added CNFs). In addition, the water contact angle of the coating with added CNF increased to 145.0°, which was 46% higher than that without the CNFs. The hydrophobicity of ceramic coatings with added CNFs was better because of changes in the surface topography. After coating and drying, the CNFs randomly accumulated inside the ceramic coating layer, forming a textured surface. Thus, hydrophobicity was improved by implementing a rugged ceramic surface without revealing the surface of the CNFs inside the ceramic layer.

Preparation of Hydrophobic Nylon Fabric

2016 ◽  
Vol 11 (1) ◽  
pp. 155892501601100
Author(s):  
Jinmei Du ◽  
Lulu Zhang ◽  
Jing Dong ◽  
Ying Li ◽  
Changhai Xu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Sem Images ◽  
Water Contact ◽  
Carboxyl Content ◽  
Factors Affecting ◽  
Nylon Fabric ◽  
Butanetetracarboxylic Acid

Surface roughness and surface energy are two important factors affecting the hydrophobicity of nylon fabric. In this study, nylon fabric was treated for hydrophobicity with tetrabutyltitanate (TBT) and octadecylamine (OA) which were respectively responsible for increasing surface roughness and reducing surface energy. In order to enhance the hydrophobicity, In order to further enhance hydrophobicity by increasing available reactive sites, 1,2,3,4–butanetetracarboxylic acid (BTCA) was applied as a pretreatment to the nylon fabric It was found that the carboxyl content of nylon was increased by the BTCA pretreatment. SEM images showed that the TBT treatment produced small particles on nylon fabric which made surface rough. The water contact angle of nylon fabric treated with BTCA, TBT and OA was measured to be 134°, which was much greater than the water contact angle of nylon fabric treated only with OA. This indicated that the surface roughness resulting from the TBT treatment played an important role in improving hydrophobicity of the treated nylon fabric. The resistance to water penetration and the repellency of water spray of nylon fabric treated with BTCA, TBT and OA were respectively measured to be 27.64 mbar and 85 out of 100.

scholarly journals Roughness and Fiber Fraction Dominated Wetting of Electrospun Fiber-Based Porous Meshes

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 34 ◽  
Author(s):  
Piotr Szewczyk ◽  
Daniel Ura ◽  
Sara Metwally ◽  
Joanna Knapczyk-Korczak ◽  
Marcin Gajek ◽  
...  
Keyword(s):  
Contact Angle ◽  
Electrospun Fiber ◽  
Three Dimensional ◽  
Contact Angles ◽  
Electrospun Fibers ◽  
Surface Geometry ◽  
Wetting Contact Angle ◽  
Fiber Fraction ◽  
Significant Difference ◽  
Entrapped Air

Wettability of electrospun fibers is one of the key parameters in the biomedical and filtration industry. Within this comprehensive study of contact angles on three-dimensional (3D) meshes made of electrospun fibers and films, from seven types of polymers, we clearly indicated the importance of roughness analysis. Surface chemistry was analyzed with X-ray photoelectron microscopy (XPS) and it showed no significant difference between fibers and films, confirming that the hydrophobic properties of the surfaces can be enhanced by just roughness without any chemical treatment. The surface geometry was determining factor in wetting contact angle analysis on electrospun meshes. We noted that it was very important how the geometry of electrospun surfaces was validated. The commonly used fiber diameter was not necessarily a convincing parameter unless it was correlated with the surface roughness or fraction of fibers or pores. Importantly, this study provides the guidelines to verify the surface free energy decrease with the fiber fraction for the meshes, to validate the changes in wetting contact angles. Eventually, the analysis suggested that meshes could maintain the entrapped air between fibers, decreasing surface free energies for polymers, which increased the contact angle for liquids with surface tension above the critical Wenzel level to maintain the Cassie-Baxter regime for hydrophobic surfaces.

Improved Hydrophobicity of Silicon Dioxide Integrated Zinc-Tellurite Glass Surface

2017 ◽  
Vol 268 ◽  
pp. 87-91
Author(s):  
Syarinie Azmi ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Glass Surface ◽  
Tellurite Glass ◽  
Hydrophobic Surfaces ◽  
Water Contact ◽  
Host Matrix ◽  
The Impact

Economically viable and maintenance free glass surfaces with improved hydrophobicity are highly demanding in the recent nanotechnology era. Deposition of pollutants and dirt on glass surface that not only causes visual obscurity but also damages the cultural heritages are still to be researched intensely. It is documented that excellent hydrophobic surfaces (with contact angle greater than 90o) can be achieved by controlling the surface wettability, where liquid droplets remain spherical on such surfaces. Selection of materials and the preparation method play a significant role towards such accomplishments. Stirred by this idea, we explored the feasibility of fabricating super-hydrophobic tellurite glass systems by facilely varying the compositions of different constituents. Highly transparent and thermally stable ternary tellurite glass system with chemical composition of (80-x)TeO2 – xSiO2 – 20ZnO, where x = 0.00 to 0.20 mol% are synthesized via conventional melt-quenching method. Samples are characterized using Atomic Force Microscopy (AFM) and contact angle measurements. The impact of SiO2 concentrations variation on the surface roughness, surface energy, and hydrophobic properties are inspected. Glass surface roughness as much as 9.885 nm is attained. The optimal value of water contact angle is discerned to be 101.02° for 0.1 mol% of SiO2 incorporation into the amorphous tellurite host matrix. Besides, the surface energy revealed an inverse proportionality to the water contact angle. This achieved contact angle (greater than 90°) makes this hydrophobic glass surface beneficial for diverse applications. It is established that the present glass composition may be prospective for the development of super-hydrophobic surfaces.

Top Layer Coating for Improving Superhydrophobic Property of Latex Cup

2017 ◽  
Vol 757 ◽  
pp. 52-56
Author(s):  
Sunisa Jindasuwan ◽  
Sitthisuntorn Supothina
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Field Test ◽  
Rubber Tree ◽  
Contact Angles ◽  
Economic Plant ◽  
Free Energy Surface ◽  
Immersion Method ◽  
Water Contact ◽  
Superhydrophobic Property

A latex cup is used to collect latex from a rubber tree which is an economic plant in Thailand. The fresh latex or crude rubber consists of organic compound and water which can wet and adhere to surface of the collecting cup. In this research, surface of the latex cup was treated with polymethylhydrogen siloxane-functionalized silica compound to improve hydrophobicity so that it could repel the dirt and latex, resulting in an anti-adhesion between the latex and the cup. Surface of the latex cup was etched with 10 % v/v hydrofluoric acid for 30 min before application of the siloxane coating which was performed by immersion in the solution, painting and spraying, respectively. The result revealed that the immersion method exhibited optimum property justified by high value of water contact angle, low surface free energy, surface roughness and the field test. At the optimum polymethylhydrogen siloxane : fumed silica ratio of 3 : 1 wt%, the treated sample had water contact angle of 139.24 ± 0.78 degrees and possessed surface energy of 1.07 mJ/m2. The field test conducted in the rubber field in Trang province revealed good durability of the coating. The water contact angles were 132.15 ± 2.05 and 129.20 ± 2.34 degrees after 2 weeks and 1 month, respectively, of the field service.

scholarly journals High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Rafik Abbas ◽  
N. Elkhoshkhany ◽  
Ahmed Hefnawy ◽  
Shaker Ebrahim ◽  
Aya Rahal
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sliding Angle ◽  
Water Contact ◽  
Stability Performance ◽  
Graphene Films ◽  
Superhydrophobic Property ◽  
Self Cleaning ◽  
Fluorinated Graphene ◽  
Highly Hydrophobic

A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

scholarly journals Investigation of the Effects of Component Ratios on the Properties of Superhydrophobic Polyurethane/Fluorinated Acrylic Co-Polymer/SiO2 Nanocomposite Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 174
Author(s):  
Chong Ke ◽  
Zhongfa Li ◽  
Chenhua Zhang ◽  
Xinguo Wu ◽  
Zhiping Zhu ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Abrasion Resistance ◽  
Light Transmittance ◽  
Practical Application ◽  
Water Contact ◽  
Glass Substrates ◽  
Superhydrophobic Coatings ◽  
One Step ◽  
Good Transparency

In this work, polyurethane/fluorinated acrylic co-polymer/silicon dioxide (PU/FAP/SiO2) hybrid superhydrophobic coatings were fabricated on glass substrates via a simple one-step coating process. The effects of each coating component on the coating properties were systematically investigated. The optimized coating exhibits a water contact angle (WCA) of 159° and a rolling angle of 3°. Meanwhile, the coating has an optical light transmittance of 88%, indicating the good transparency of the coating. Besides, the coating demonstrates an adequate level of abrasion resistance. After a total abrasion distance of 300 cm against a piece of 800 mesh sand paper, the sample still kept a water contact angle of about 110°, showing its high abrasion resistance. Therefore, the optimized coating has a great potential for practical application.

scholarly journals Measurements of surface free energy as a tool to asses the effect of varnishing and printing of the paper substrates

2020 ◽  
Author(s):  
Zuzanna Żołek-Tryznowska ◽  
◽  
Marta Więcek ◽  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Water Contact Angle ◽  
Water Contact ◽  
Human Eye ◽  
Varnish Layer ◽  
Energy Determination ◽  
Paper Substrates

Nowadays, printing products might be finished in various ways. Varnishing process is one of the most popular finishing method which gives various effect, such as mate, glossy etc. However, the varnish layer applied on the paper is very thin, therefore it can be invisible to the naked human eye. The aim of this work was to use contact angle measurement and surface free energy determination as a tool to assess the effect of printing and varnishing process of paper materials. We have used various tools in order to analyses the changes of surface: surface roughness, gloss, water contact angle absorption and surface free energy determination. Those tools were used in order to confirm whether the print has been covered with varnish or not. In this work six various paper substrates were used (glossy, coated and un-coated papers). The printing and varnishing was performed in laboratory conditions using flexographic water-based printing and waterbased varnish. Samples were prepared as follows: paper with ink coating, paper with varnish coating and paper with ink layer and varnish layer on the top. The surface roughness was determinated of all samples and compared. The surface roughness changes were observed for pure paper, overprinted and overvarnished. Next, the gloss of samples prior and after printing and varnishing was measured. The gloss of the samples increases when they are printed or varnished, what is related with properties of ink and varnish. Also, the thickness of ink and varnish layers was determinated. The thickness of the samples increases when the number of layers increases. Finally, the water contact angle was measured and surface free energy was calculated with Owens-Wendt method. Our results reveal the possibility of using various tools in order to confirm the performance of varnishing of the prints. The printing with various colors is always seen by the naked human eye. On the other hand, the varnish layer might be not visible. However, such a comparison is not possible if we do not have the pure paper substrates prior printing or varnish.

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