Characterizing the Impact of Temperature on Clay-Water Contact Angle in Geomaterials during Extreme Events by Deep Learning Enhanced Method

2021 ◽  
Author(s):  
Zhe Zhang ◽  
Xiaoyu Song
Keyword(s):  
Contact Angle ◽  
Deep Learning ◽  
Water Contact Angle ◽  
Extreme Events ◽  
Water Contact ◽  
The Impact

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.

scholarly journals Do bevacizumab solutions interact with silicone or polyurethane catheters during an infusion through implantable venous access ports?

2019 ◽  
Vol 16 (158) ◽  
pp. 20180721
Author(s):  
Nicolas Tokhadzé ◽  
Philip Chennell ◽  
Régis Cueff ◽  
Valérie Sautou
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Angle Measurement ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Water Contact ◽  
Physico Chemical ◽  
Polyurethane Catheters ◽  
The Impact

This work aims to evaluate the possible impact of interactions between bevacizumab solutions and an implantable port equipped with a silicone or a polyurethane catheter after infusion through a complete infusion set-up in simulated use conditions. Physico-chemical and structural stability of bevacizumab solution was assessed by visual examination, subvisible particles counting, dynamic light scattering, size exclusion chromatography and ion exchange chromatography. Mechanical properties of the catheters were evaluated by measuring Shore A hardness, strain at break, strain at stress and Young's modulus. The physico-chemical surface state of the catheters was assessed by FTIR-ATR spectroscopy, scanning electron microscopy (SEM) and by water contact angle measurement. The analysis of the bevacizumab solution did not highlight any signs of instability or loss of active substance. Mechanical properties of both materials remained unchanged after the infusion. During material analysis, a decrease in water contact angle observed after infusion and was more pronounced for polyurethane catheters than for silicone, possibly due to bevacizumab adsorption or possible leachable extraction from the materials. Surface modifications were also noted at SEM. This study did not highlight any modifications that could alter the quality of the bevacizumab infusion, nor of the infusion catheter in polyurethane or silicone, despite a modification of surface hydrophilicity. Even if after a single infusion, implantable ports remained safe to use, they aim to be used for several infusion of various drugs during their lifetime, and further studies are needed to assess the impact of repeated infusions.

Influence of Electrospinning Parameters on the Hydrophilicity of Electrospun Polycaprolactone Nanofibres

2019 ◽  
Vol 19 (11) ◽  
pp. 7251-7260 ◽  
Author(s):  
Ismail Tiyek ◽  
Aysegul Gunduz ◽  
Fatma Yalcinkaya ◽  
Jiri Chaloupek
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Wound Dressing ◽  
Polymer Concentration ◽  
Solvent Mixtures ◽  
Water Contact ◽  
Simple Method ◽  
Etoh Solution ◽  
Solvent Systems ◽  
The Impact

In the present study, PCL (polycaprolactone) nanofibres were produced by the electrospinning method. The use of PCL electrospun biopolymer in biomedical applications has attracted considerable interest due to its chemical resistance, biodegradability, biocompatibility, and non-toxic characteristics. However, the hydrophobic nature of PCL polymer restricts the useage of PCL nanofibres for the cell adhesion and absorption. A hydrophilic and biocompatible PCL electrospun mat with a low water contact angle is an attractive strategy for development in tissue engineering and wound dressing. In this study, we demonstrate a feasible and simple method to produce hydrophilic PCL nanofibres for possible application in wound dressing. Chloroform/ethanol (EtOH) and chloroform/dimethylformamide (DMF) mixtures were used as two different solvent systems. The impact of the polymeric solution concentration, applied voltage, and solvent mixtures on the fibre surface morphology and water contact angle was investigated. Consequently, bead structures were observed at low concentrations but disappeared with increases in the concentration. It was observed that the size of beads decreased and the diameter of fibres increased with increasing voltage. The wettability of the webs changed from hydrophobic to hydrophilic with changes of the polymer concentration. The contact angle of the nanofibre mats decreased in both solvent systems as the concentration increased. The results showed that the lowest contact angle was obtained in 24% wt. PCL+chloroform/EtOH solution and was 68°. The highest contact angle was obtained in 4% wt. PCL+chloroform/EtOH solution and was 112°. Using this method, the surface hydrophilicity of the PCL nanofibres improved easily without any surface treatment.

Effect of Altering the Sequence of Chempolishing and Electropolishing on Surface Properties of Additively Manufactured (AM) 316 Steel Components

2020 ◽  
Author(s):  
Joshua Dillard ◽  
Andrew Grizzle ◽  
Wondwosen Demisse ◽  
Pawan Tyagi ◽  
Lucas Rice ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Protective Coatings ◽  
Rough Surfaces ◽  
Stress Raiser ◽  
Internal Surface ◽  
Surface Finishing ◽  
Water Contact ◽  
The Impact

Abstract The surface roughness of as produced additively manufactured (AM) components is very high and may lead to component failure and undesirable coefficients of friction. In rough surfaces, small cracks form at regions of high surface roughness acting as a stress raiser or crack nucleation sites. Likewise, rough surfaces impact both static and kinetic friction that can impede desired motion and oppose desired mechanical forces. For using these components in many applications, it is necessary to reduce surface deviations drastically during postprocessing. For parts with complex geometries and enormous internal surface areas, this reduction presents a complex engineering problem. We have explored chempolishing (C) and electropolishing (E) to reduce the external and internal surface roughness of stainless-steel components in our previous studies. Chempolishing is an electroless etching process that can uniformly smoothen the accessible surfaces of complex AM components. Electropolishing can produce an extremely smooth surface to sub-micrometer level roughness. Our prior work showed that chempolishing and electropolishing produced very distinct surface microstructures. It is quite possible that in future surface finishing, chempolishing and electropolishing may be applied on the same AM component to reduce the surface roughness of complex AM components. The resulting microstructure after the sequential application of chempolishing and electropolishing may be quite different as compared to that of after chempolishing or electropolishing alone. Here, we report the application of altering the sequence of chempolishing and electropolishing to reduce the external and internal surface roughness of 316 steel components. It is unknown what will be the impact of manipulating the sequence of electropolishing and chemical polishing on surface roughness and microstructure of AM materials. This paper focuses on the post-process sequencing of chempolishing, followed by electropolishing (CE) and vice versa (EC). We found chempolishing followed by electropolishing reduced internal surface roughness by as much as 12 micrometers. Whereas the electropolishing followed by chempolishing reduced external surface roughness by an average of ∼15 micrometers. The structure and properties of the surface finished pieces were examined using: Scanning Electron Microscopy (SEM), Surface Profilometry, and Water Contact Angle Measurement. SEM provided direct insight that CE and EC process produced significantly different microstructures from each other and also from chempolished and electropolished processes. Water contact angle measurements performed on CE, and EC treated AM samples showed that surface energy was quite different. Hence, CE and EC are expected to perform quite differently under a corrosive environment and also yield various adhesion quality for the protective coatings. Confirmation of structural changes provided in this experiment shed light on the capabilities of postprocessing improvements we can make to materials performance.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

Sign in / Sign up

Export Citation Format

Share Document