Effects of simulated acid rain on needle wettability and rain retention by two Sitka spruce (Piceasitchensis) clones

1991 ◽  
Vol 21 (5) ◽  
pp. 694-697 ◽  
Author(s):  
K. E. Percy ◽  
E. A. Baker
Keyword(s):  
Contact Angle ◽  
Ion Exchange ◽  
Acid Rain ◽  
Surface Properties ◽  
Sitka Spruce ◽  
Contact Angles ◽  
Simulated Acid Rain ◽  
Sodium Fluorescein ◽  
Simulated Rain

The effect of simulated rain acidity (pH 2.6, 3.4, 4.2, and 5.6) on wettability and rain retention was investigated for elongating needles on stecklings of two Sitka spruce (Piceasitchensis) (Bong.) Carr) clones over an 11-week period. There were highly significant differences in contact angle between pH treatments, clones, and sample dates. Contact angles on needles of both clones exposed at pH ≤ 4.2 were significantly smaller than those on needles exposed at pH 5.6. Needles from both clones exposed to simulated rain at pH ≤ 4.2 retained significantly more simulated rain containing sodium fluorescein. These changes to needle surface properties following realistic exposure to simulated acid rain could have important consequences for processes occurring at the phylloplane, such as ion exchange.

Diamond-Like Carbon Films for Silicon Passivation in Microelectromechanical Devices

1995 ◽  
Vol 383 ◽  
Author(s):  
M. R. Houston ◽  
R. T. Howe ◽  
K Komvopoulos ◽  
R. Maboudian
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Microelectromechanical Systems ◽  
Adhesion Force ◽  
Contact Angles ◽  
Vacuum Arc ◽  
Diamond Like Carbon ◽  
Adhesion Forces ◽  
Water Contact

ABSTRACTThe surface properties of diamond-like carbon (DLC) films deposited by a vacuum arc technique on smooth silicon wafers are presented with specific emphasis given to stiction reduction in microelectromechanical systems (MEMS). The low deposition temperatures afforded by the vacuum arc technique should allow for easy integration of the DLC films into the current fabrication process of typical surface micromachines by means of a standard lift-off processing technique. Using X-ray photoelectron spectroscopy (XPS), contact angle analysis, and atomic force microscopy (AFM), the surface chemistry, microroughness, hydrophobicity, and adhesion forces of DLC-coated Si(100) surfaces were measured and correlated to the measured water contact angles. DLC films were found to be extremely smooth and possess a water contact angle of 87°, which roughly corresponds to a surface energy of 22 mJ/m2. It is shown that the pull-off forces measured by AFM correlate well with the predicted capillary forces. Pull-off forces are reduced on DLC surfaces by about a factor of five compared to 10 nN pull-off forces measured on the RCA-cleaned silicon surfaces. In the absence of meniscus forces, the overall adhesion force is expected to decrease by over an order of magnitude to the van der Waals attractive force present between two DLC-coated surfaces- To further improve the surface properties of DLC, films were exposed to a fluorine plasma which increased the contact angle to 99° and lowered the pull-off force by approximately 20% over that obtained with as-deposited DLC. The significance of these results is discussed with respect to stiction reduction in micromachines.

The Effect of Drop Volume on Contact Angle

1991 ◽  
Vol 54 (3) ◽  
pp. 232-235 ◽  
Author(s):  
JOSEPH MCGUIRE ◽  
JIANGUO YANG
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Solid Surface ◽  
Contact Surface ◽  
Contact Angles ◽  
Equilibrium Contact Angle ◽  
Drop Volume ◽  
Food Contact ◽  
Food Contact Surface ◽  
Limiting Value

The effect of drop volume on the equilibrium contact angle, used in evaluation of food contact surface properties, was measured for liquids exhibiting both polar and nonpolar character on six different materials. Drop volumes used ranged from 2 to 40 μl. Contact angles were observed to increase with increasing drop volume in a range below some limiting value, identified as the critical drop volume (CDV). The CDV varied among materials and is explained with reference to surface energetic heterogeneities exhibited by each type of solid surface.

scholarly journals Modification of Surface Hydrophobicity of PLA/PE and ABS/PE Polymer Blends by ICP Etching and CFx Coating

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5578
Author(s):  
Vedrana Lovinčić Milovanović ◽  
Cédric Guyon ◽  
Ivana Grčić ◽  
Michael Tatoulian ◽  
Domagoj Vrsaljko
Keyword(s):  
Contact Angle ◽  
3D Printing ◽  
Surface Morphology ◽  
Polymer Blends ◽  
Surface Properties ◽  
Surface Hydrophobicity ◽  
Contact Angles ◽  
Etching Time ◽  
Fused Filament Fabrication ◽  
Icp Etching

The flow regime inside the channel of 3D printed microreactors is defined by the surface properties of the channel walls. Polylactide (PLA) and acrylonitrile/butadiene/styrene (ABS) are two polymers that are the most common in additive manufacturing using fused filament fabrication, commonly known as “3D printing”. With the aim of developing new materials for the 3D printing of microreactors whose channel surface hydrophobicity could be modified, PLA and ABS were blended with cheaper and widely used polymers-high-density polyethylene (PE-HD) and low-density polyethylene (PE-LD). Polymer blend surfaces were treated with inductively coupled plasma (ICP) and coated by fluorocarbon-based material (CFx) plasma deposition treatment in order to modify surface hydrophobicity. It has been shown that the modification of surface morphology of PLA polymer blends can be achieved by ICP etching and CFx coating, while this was not possible for ABS polymer blends under the conducted treatment conditions. The treated surface of PLA/PE-HD 90/10 showed a contact angle of 121.6° which is 36° higher than the contact angle measured on the untreated surface. Surfaces that have achieved contact angles higher than 120° have an “island like” surface morphology. Samples with higher “islands” showed higher contact angles, that confirmed that the hydrophobicity also depends on the height of the “islands”. Furthermore, it has been found that etching time significantly impacts the contact angle values and surface morphology of the PLA polymer blends, while the CFx coating time does not have significant impact on the surface properties.

Influence of simulated acid rain on the flowering dogwood (Cornusflorida) leaf surface

1994 ◽  
Vol 24 (5) ◽  
pp. 1058-1062 ◽  
Author(s):  
Daniel A. Brown ◽  
Mark T. Windham ◽  
Robert L. Anderson ◽  
Robert N. Trigiano
Keyword(s):  
United States ◽  
Acid Rain ◽  
Leaf Surface ◽  
Simulated Acid Rain ◽  
Eastern United States ◽  
Flowering Dogwood ◽  
Simulated Rain ◽  
Decreasing Ph ◽  
One Year ◽  
Scanning Electron

Acidic rainfall has the potential to influence anthracnose incidence and severity in flowering dogwood (Cornusflorida L.) of the eastern United States. One-year-old, nursery-grown flowering dogwood seedlings were exposed to 1 cm of simulated rain 10 times over a 42-day period in 1990. Simulated rains were composed of a mixture of salts typical of ambient rainfall in the eastern United States and pH was adjusted to 5.5, 4.5, 3.5, and 2.5 with sulfuric and nitric acids. Samples were cut from the leaf tip, margin, and midvein of rain-treated trees and prepared for scanning electron microscopy. Cuticular cracking, desiccation, and erosion of trichome surfaces was observed in response to acid rain treatment. Increased degradation of dogwood trichomes was observed with decreasing pH for all samples. Cuticular erosion due to acid rain has the potential to predispose dogwoods in the eastern United States to anthracnose caused by Disculadestructiva sp.nov. (Red.) and an unnamed Discula sp.

Effects of green technology plasma pre-treatment on the wettability and ink adhesion of paper

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samed Ayhan Özsoy ◽  
Safiye Meriç Acıkel ◽  
Cem Aydemir
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Surface Properties ◽  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Contact Angles ◽  
Content Type ◽  
Surface Energies ◽  
Pressure Plasma ◽  
Plasma Device

Purpose The surface energy of the printing material can be increased to desired levels with different chemicals or methods. However, the important thing is that the surface properties of printing material are not affected negatively. In this way the aim of this paper provide that the surface properties of matte and glossy coated paper is improved by the argon containing atmospheric pressure plasma device because the plasma treatment method does not occur surface damaging on the papers. Design/methodology/approach In experimental studies, test samples cut from 160 mm × 30 mm in size from 115 g/m2 gloss- and matt-coated papers were used. The plasma treatments of paper samples were carried out with an argon containing atmospheric pressure plasma device of laboratory scale that produces plasma of the corona discharge type at radio frequency. The optimized plasma parameters were at a frequency of 20 kHz and plasma power 200 W. A copper electrode of length 12 cm and diameter 2.5 mm was placed in the centre of the nozzle. Findings Research findings showed that the surface energies of the papers increased with the increase in plasma application time. While the contact angle of the untreated glossy paper is 82.2, 8 second plasma applied G3 sample showed 54 contact angle value. Similarly, the contact angle of the base paper of matt coated is 91.1, while M3 is reduced to 60.4 contact angles by the increasing plasma time. Originality/value Plasma treatment has shown that no chemical coating is needed to increase the wettability of the paper surface by reducing the contact angle between the paper and the water droplet. In addition, the surface energies of all papers treated by argon gas containing atmospheric pressure plasma, increased. Plasma treatment provides to improve both the wettability of the paper and the adhesion property required for the ink, with an environmentally friendly approach.

Impact of Simulated Acid Rains on Nitrogenase Activity in Peltigera Aphthosa and P. Polydactyla

1985 ◽  
Vol 17 (1) ◽  
pp. 27-31 ◽  
Author(s):  
R. P. Fritz-Sheridan
Keyword(s):  
Nitrogen Fixation ◽  
Acid Rain ◽  
North American ◽  
Nitrogenase Activity ◽  
Simulated Acid Rain ◽  
Complete Inhibition ◽  
Simulated Rain

AbstractTwo ubiquitous diazotrophic North American lichens, Peltigera aphthosa and P. polydaclyla, were subjected to simulated acid rain. Both lichens exhibited a 50% reduction in nitrogen fixation at pH 5, 80% reduction at pH 4 and complete inhibition at pH 2. Nitrogen fixation was zero after 20 days exposure to simulated rain at pH 3 and zero after fourdays at pH 2.

scholarly journals Fabrication of Robust Superhydrophobic Bamboo Based on ZnO Nanosheet Networks with Improved Water-, UV-, and Fire-Resistant Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jingpeng Li ◽  
Qingfeng Sun ◽  
Qiufang Yao ◽  
Jin Wang ◽  
Shenjie Han ◽  
...  
Keyword(s):  
Contact Angle ◽  
Acid Rain ◽  
Modern Society ◽  
Simulated Acid Rain ◽  
High Contact Angle

Bamboo with water-resistant, UV-resistant, and fire-resistant properties was desirable in modern society. In this paper, the original bamboo was firstly treated with ZnO sol and then hydrothermally the ZnO nanosheet networks grow onto the bamboo surface and subsequently modified with fluoroalkyl silane (FAS-17). The FAS-17 treated bamboo substrate exhibited not only robust superhydrophobicity with a high contact angle of 161° but also stable repellency towards simulated acid rain (pH = 3) with a contact angle of 152°. Except for its robust superhydrophobicity, such a bamboo also presents superior water-resistant, UV-resistant, and fire-resistant properties.

The Wetting of Insect Cuticles by Water

1955 ◽  
Vol 32 (3) ◽  
pp. 591-617 ◽  
Author(s):  
M. W. HOLDGATE
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Properties ◽  
Surface Composition ◽  
Contact Angles ◽  
Aquatic Species ◽  
Water Contact ◽  
Calliphora Erythrocephala ◽  
Wetting Properties ◽  
Wide Range

1. The water contact angles of insects show a wide range of variation, which is broadly correlated with surface roughness and with habitat. 2. The contact angles of species inhabiting stored products or carrion are greatly modified by contamination. This produces large variations between apparently similar individuals. 3. In terrestrial insects surface roughness increases the contact angles to very large apparent values. Detailed analyses of its effect have been made in the pupa of Tenebrio molitor and the adult Calliphora erythrocephala. In some aquatic insects surface roughness leads to a reduction in the contact angles; this has been studied in the nymph of Anax imperator. 4. Prolonged immersion in water causes a lowering of the contact angles of all the insects examined, and the low angles of many aquatic species may therefore be the direct effect of their environment. In some aquatic species there is evidence of the active maintenance of a large contact angle during life. 5. Changes in contact angle accompany processes of cuticle secretion and will occur at any moult if changes in roughness or habitat take place. 6. The observed variations of surface properties can be explained without assuming any variation in the chemical composition of the cuticle surface. Wetting properties are of little value as indicators of cuticle surface composition. 7. The biological aspects of insect surface properties are briefly discussed.

CHARACTERIZATION OF DYNAMIC WETTING OF PLASMA-TREATED PTFE FILM

2007 ◽  
Vol 14 (04) ◽  
pp. 821-825 ◽  
Author(s):  
Q. F. WEI ◽  
Y. LIU ◽  
F. L. HUANG ◽  
S. H. HONG
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Surface Properties ◽  
Contact Angle Hysteresis ◽  
Frictional Coefficient ◽  
Dynamic Contact Angle ◽  
Contact Angles ◽  
Dynamic Wetting ◽  
Ptfe Film ◽  
Receding Contact

Polytetrafluoroethylene (PTFE) has been increasingly used in many industries due to its low frictional coefficient and excellent chemical inertness. The surface properties of PTFE are of importance in various applications. The surface properties of PTFE can be modified by different techniques. In this study, PTFE film was treated in oxygen plasma for improving surface wettability. The effects of plasma treatment on dynamic wetting behavior were characterized using Scanning Probe Microscopy (SPM), Fourier transform infrared spectroscopy (FTIR), and dynamic contact angle (DCA) measurements. SPM observations revealed the etching effect of the plasma treatment on the film. The introduction of hydrophilic groups by plasma treatment was detected by FTIR. The roughened and functionalized surface resulted in the change in both advancing and receding contact angles. Advancing and receding contact angles were significantly reduced, but the contact angle hysteresis was obviously increased after plasma treatment.

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