scholarly journals Enhancing Water and Oil Repellency of Teflon Surface By Imparting Micro-Rough Structures Using Simple One-Step

2017 ◽  
Vol 5 (3) ◽  
pp. 266
Author(s):  
Khedir R. Khedir
Keyword(s):  
Surface Tension ◽  
Work Of Adhesion ◽  
Organic Liquids ◽  
Particle Sizes ◽  
Sliding Angle ◽  
Wide Range ◽  
Water Glycerol ◽  
One Step ◽  
Micro Structures ◽  
Inexpensive Technique

In this work, an easy one-step and inexpensive technique of mechanical wet sanding was used to impart micro structures into the Teflon surface that promotes super repellent properties toward water and the two moderate low surface tension organic liquids. Sandpapers with a wide range of grit sizes 60-1000, with associated particle sizes of 256-10 µm, were used to obtain physical modification of the Teflon surface. The roughened Teflon surface with the sandpaper of 400 grit size showed super repellency toward water, glycerol, and ethylene glycol with CAs as high as 158°, 150°, and 142°, respectively, as well as the low sliding angle of less than 2°, 5°, and 15°, respectively. The obtained results and the effect of roughness were explained in terms of both fundamental wetting models of Wenzel and Cassie-Baxter. The effect of a decrease in liquid surface tension on the length scale of imparted geometries and consequent wetting state was also concluded. Finally, the work of adhesion for the tested liquids while on the roughened Teflon surfaces were also determined using both Young-Dupre relation and the liquid’s SAs.

Molecular Dynamics Study of Anatase TiO2 Nanoparticles in Water and Vacuum Environments

2012 ◽  
Author(s):  
George Okeke ◽  
Robert B. Hammond ◽  
S. Joseph Antony
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Surface Energy ◽  
Tio2 Nanoparticles ◽  
Anatase Tio2 ◽  
Particle Sizes ◽  
Metallic Oxides ◽  
Wide Range ◽  
Enhanced Properties ◽  
Dynamics Simulations

Nanoparticles are nanometer sized metallic oxides which possess enhanced properties that are desirable to a wide range of industries. In this study, we investigate structural and surface properties of anatase TiO2 nanoparticles in vacuum and water environments using molecular dynamics simulations. The particle sizes ranged from 2 to 6 nm and simulations were performed at 300 K. Surface energy of the particles in vacuum was seen to be higher than that of the particles in water by about 100% for the smaller particles (i.e. 2 and 3nm) and about 60% for the larger particles (i.e. 4 to 6 nm). Surface energy of the particles in both environments, is seen to increase to a maximum (optimum value) as the particle size increases after which no further significant increase is observed. In vacuum, studies carried out at temperatures ranging from 300–2500 K showed a high dependence of surface energy on temperature. The estimated surface tension of water is seen to agree quite well with that of experiments.

Effects of Fluid Properties on Spray Characteristics of a Flow-Blurring Atomizer

2017 ◽  
Author(s):  
Brian T. Fisher ◽  
Michael R. Weismiller ◽  
Steven G. Tuttle ◽  
Katherine M. Hinnant
Keyword(s):  
Surface Tension ◽  
Axial Direction ◽  
Lower Surface ◽  
Spray Characteristics ◽  
Characteristic Distance ◽  
Phase Doppler Anemometry ◽  
Wide Range ◽  
Fluid Properties ◽  
Water Glycerol ◽  
Droplet Sizes

In order to understand the reasons for the apparent benefits of using a flow-blurring (FB) atomizer in a combustion system, it is necessary to first examine fundamental spray characteristics under non-reacting conditions. Previous work on FB atomizers, however, has mostly involved only water and a relatively narrow range of parameters. In this study, a phase Doppler anemometry instrument was used to characterize FB atomizer sprays and determine the effects of varying surface tension and viscosity of the liquid. Operating at room pressure and temperature (i.e., a “cold spray”), droplet sizes and velocities were measured for water, a water/surfactant mixture (lower surface tension), a water/glycerol mixture (higher viscosity), and glycerol (much higher viscosity). For all of the tested fluids, with the exception of pure glycerol, the FB atomizer produced small droplets (below 50 μm) whose size did not vary significantly in the radial or axial direction, particularly above a characteristic distance from the atomizer exit. Results show that the spray is essentially unaffected by a 4.5x decrease in surface tension or a 7x increase in viscosity, and that Sauter mean diameter (SMD) only increased by approximately a factor of three when substituting glycerol (750x higher viscosity) for water. The results suggest that the FB atomizer can effectively atomize a wide range of liquids, making it a useful fuel-flexible atomizer for combustion applications.

Effects of Fluid Properties on Spray Characteristics of a Flow-Blurring Atomizer

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Brian T. Fisher ◽  
Michael R. Weismiller ◽  
Steven G. Tuttle ◽  
Katherine M. Hinnant
Keyword(s):  
Surface Tension ◽  
Axial Direction ◽  
Lower Surface ◽  
Spray Characteristics ◽  
Characteristic Distance ◽  
Phase Doppler Anemometry ◽  
Wide Range ◽  
Fluid Properties ◽  
Water Glycerol ◽  
Droplet Sizes

In order to understand the reasons for the apparent benefits of using a flow-blurring (FB) atomizer in a combustion system, it is necessary to first examine fundamental spray characteristics under nonreacting conditions. Previous work on FB atomizers, however, has mostly involved only water and a relatively narrow range of parameters. In this study, a phase Doppler anemometry (PDA) instrument was used to characterize FB atomizer sprays and determine the effects of varying surface tension and viscosity of the liquid. Operating at room pressure and temperature (i.e., a “cold spray”), droplet sizes and velocities were measured for water, a water/surfactant mixture (lower surface tension), a water/glycerol mixture (higher viscosity), and glycerol (much higher viscosity). For all of the tested fluids, with the exception of pure glycerol, the FB atomizer produced small droplets (below 50 μm) whose size did not vary significantly in the radial or axial direction, particularly above a characteristic distance from the atomizer exit. Results show that the spray is essentially unaffected by a 4.5× decrease in surface tension or a 7× increase in viscosity, and that Sauter mean diameter (SMD) only increased by approximately a factor of three when substituting glycerol (750× higher viscosity) for water. The results suggest that the FB atomizer can effectively atomize a wide range of liquids, making it a useful fuel-flexible atomizer for combustion applications.

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

scholarly journals One-step preparation of antimicrobial silicone materials based on PDMS and salicylic acid: insights from spatially and temporally resolved techniques

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Luca Barbieri ◽  
Ioritz Sorzabal Bellido ◽  
Alison J. Beckett ◽  
Ian A. Prior ◽  
Jo Fothergill ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Pharmaceutical Products ◽  
Laser Scanning Microscopy ◽  
Wound Dressings ◽  
Confocal Laser ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
One Step

AbstractIn this work, we introduce a one-step strategy that is suitable for continuous flow manufacturing of antimicrobial PDMS materials. The process is based on the intrinsic capacity of PDMS to react to certain organic solvents, which enables the incorporation of antimicrobial actives such as salicylic acid (SA), which has been approved for use in humans within pharmaceutical products. By combining different spectroscopic and imaging techniques, we show that the surface properties of PDMS remain unaffected while high doses of the SA are loaded inside the PDMS matrix. The SA can be subsequently released under physiological conditions, delivering a strong antibacterial activity. Furthermore, encapsulation of SA inside the PDMS matrix ensured a diffusion-controlled release that was tracked by spatially resolved Raman spectroscopy, Attenuated Total Reflectance IR (ATR-IR), and UV-Vis spectroscopy. The biological activity of the new material was evaluated directly at the surface and in the planktonic state against model pathogenic bacteria, combining confocal laser scanning microscopy, electron microscopy, and cell viability assays. The results showed complete planktonic inhibition for clinically relevant strains of Staphylococcus aureus and Escherichia coli, and a reduction of up to 4 orders of magnitude for viable sessile cells, demonstrating the efficacy of these surfaces in preventing the initial stages of biofilm formation. Our approach adds a new option to existing strategies for the antimicrobial functionalisation of a wide range of products such as catheters, wound dressings and in-dwelling medical devices based on PDMS.

Surface Tension Estimation of Binary System of Several Organic Liquids

2010 ◽  
Vol 28 (5) ◽  
pp. 469-476
Author(s):  
A. A. Saleh ◽  
H. A. A. Algane ◽  
E. T. Hashim
Keyword(s):  
Surface Tension ◽  
Binary System ◽  
Organic Liquids

Effects of fines on liquefaction behaviour in well-graded materials

2017 ◽  
Vol 54 (10) ◽  
pp. 1460-1471 ◽  
Author(s):  
Katherine A. Kwa ◽  
David W. Airey
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
State Parameter ◽  
Triaxial Tests ◽  
Particle Sizes ◽  
Graded Materials ◽  
Fines Content ◽  
Cyclic Resistance ◽  
Wide Range ◽  
Soil Behaviour

This study uses a critical state soil mechanics perspective to understand the mechanics behind the liquefaction of metallic ores during transport by ship. These metallic ores are transported at relatively low densities and have variable gradings containing a wide range of particle sizes and fines contents. The effect of the fines content on the location of the critical state line (CSL) and the cyclic liquefaction behaviour of well-graded materials was investigated by performing saturated, standard drained and undrained monotonic and compression-only cyclic triaxial tests. Samples were prepared at four different gradings containing particle sizes from 9.5 mm to 2 μm with fines (<75 μm) contents of 18%, 28%, 40%, and 60%. In the e versus log[Formula: see text] plane, where e is void ratio and [Formula: see text] is mean effective stress, the CSLs shifted upwards approximately parallel to one another as the fines content was increased. Transitional soil behaviour was observed in samples containing 28%, 40%, and 60% fines. A sample’s cyclic resistance to liquefaction depended on a combination of its density and state parameter, which were both related to the fines content. Samples with the same densities were more resistant to cyclic failure if they contained higher fines contents. The state parameter provided a useful prediction for general behavioural trends of all fines contents studied.

scholarly journals One-step preparation of Cr2O3-based ink with long-term dispersion stability for inkjet applications

2021 ◽  
Author(s):  
Dongjin Xie ◽  
Qiuyi Luo ◽  
Shen Zhou ◽  
Mei Zu ◽  
Haifeng Cheng
Keyword(s):  
High Precision ◽  
Inkjet Printing ◽  
Printed Electronics ◽  
Direct Writing ◽  
Deposition Technique ◽  
Functional Material ◽  
Wide Range ◽  
One Step ◽  
Oled Display

Inkjet printing of functional material has shown a wide range of application in advertzing, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition technique. Nevertheless,...

Plasticity contributions to interface adhesion in thin-film interconnect structures

2000 ◽  
Vol 15 (12) ◽  
pp. 2758-2769 ◽  
Author(s):  
Michael Lane ◽  
Reinhold H. Dauskardt ◽  
Anna Vainchtein ◽  
Huajian Gao
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Fracture Energy ◽  
Fracture Resistance ◽  
Work Of Adhesion ◽  
Interface Fracture ◽  
Cohesive Stress ◽  
Wide Range ◽  
Macroscopic Fracture ◽  
Metal Layers

The effects of plasticity in thin copper layers on the interface fracture resistance in thin-film interconnect structures were explored using experiments and multiscale simulations. Particular attention was given to the relationship between the intrinsic work of adhesion, Go, and the measured macroscopic fracture energy, Gc. Specifically, the TaN/SiO2 interface fracture energy was measured in thin-film Cu/TaN/SiO2 structures in which the Cu layer was varied over a wide range of thickness. A continuum/FEM model with cohesive surface elements was employed to calculate the macroscopic fracture energy of the layered structure. Published yield properties together with a plastic flow model for the metal layers were used to predict the plasticity contribution to interface fracture resistance where the film thickness (0.25–2.5 μm) dominated deformation behavior. For thicker metal layers, a transition region was identified in which the plastic deformation and associated plastic energy contributions to Gc were no longer dominated by the film thickness. The effects of other salient interface parameters including peak cohesive stress and Go are explored.

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