Droplet rolling angle model of micro-nanostructure superhydrophobic coating surface

2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Jinyu Chen ◽  
Junwu Chen ◽  
Lee Li ◽  
Shengwu Wang ◽  
Yi Xie
2010 ◽  
Vol 119 (1-2) ◽  
pp. 40-47 ◽  
Author(s):  
Zhuangzhu Luo ◽  
Zhaozhu Zhang ◽  
Wenjing Wang ◽  
Weimin Liu ◽  
Qunji Xue

2008 ◽  
Vol 20 (5) ◽  
pp. 970-974 ◽  
Author(s):  
Z. Z. Luo ◽  
Z. Z. Zhang ◽  
L. T. Hu ◽  
W. M. Liu ◽  
Z. G. Guo ◽  
...  

2013 ◽  
Vol 743-744 ◽  
pp. 504-508
Author(s):  
Zhen Zhang ◽  
Hui You Zhao ◽  
Yu Lin Chen ◽  
De Shun Sun ◽  
Cheng Song Fu

Fly ash, as a raw materials,is used to prepare micro-nanostructural beads with the surface modified by using silane coupling agent. The coating of micro-nanostructural surface was prepared by using the modified micro-nanostructural beads and silicone rubber adhesive. Then the coating surface was dipped in liquid teflon (PTFE) for hydrophobic modification. Scanning Electronic Microscope (SEM) and JC2000C contact angle tester were used to character the coating surface performance. The results show that the average contact angle and rolling angle of the coating surface are measured as 152.9° and 3.4° respectively which means the prepared coating being of super-hydrophobicity.


2020 ◽  
Vol 25 (3) ◽  

100% humidity and the presence in the air of such corrosion stimulants as CO2, NH3 and H2S are characteristic of livestock buildings. Under these conditions, a surface phase film of moisture is formed on the surface of the metals in which the indicated micro-mixtures of air are dissolved and hydrated almost completely with the formation of NH4OH and acids H2CO3 and H2S. The potentiodynamic polarization method was used to study the corrosion and kinetics of electrode processes on steel with a superhydrophobic coating in a NaCl background solution (used to provide sufficient electrical conductivity) saturated in pairs with CO2 and NH3, NH3 and H2S. Similar studies were conducted with uncoated electrodes. Superhydrophobic coating was obtained on the basis of laser texturing of the surface with subsequent hydrophobization with fluoroxysilane (wetting angle 165±2°, rolling angle 3±1°). The influence of the duration of the exposure of the electrodes in solution (0,25…168 h) on the kinetics of electrode processes and the corrosion rate of steel is considered. In the presence of CO2 and NH3 dissolution products, the corrosion rate of an electrode with a superhydrophobic coating on the second and third days of exposure is about an order of magnitude, and on the fourth and seventh days it is more than an order of magnitude lower than without coating. During the entire time the electrodes are in solution, the anode process on the superhydrophobic electrode is inhibited compared to an unprotected electrode. The medium containing the dissolution products of NH3 and H2S is more aggressive than the previous solution. Therefore, the corrosion rate of the electrodes without coating and with a coating here is higher than in the latter one. The corrosion rate of electrodes with superhydrophobic coating in the study period is only 1,5…2,5 times lower than that of uncoated electrodes. During the first day of exposure, the anode process is inhibited, and in the next 144 hours, on the contrary, it is facilitated in comparison with an unprotected electrode. Taking into account the corrosivity of the chloride solution, the possible effect of the dissolution products of aggressive air micro-impurities in the absence of background salt was analyzed.


Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 219
Author(s):  
Mitsugu Hasegawa ◽  
Haruka Endo ◽  
Katsuaki Morita ◽  
Hirotaka Sakaue ◽  
Shigeo Kimura

A hybrid anti-/de-icing system combining a superhydrophobic coating and an electrothermal heater is an area of active research for aircraft icing prevention. The heater increases the temperature of the interaction surface between impinging droplets and an aircraft surface. One scientific question that has not been studied in great detail is whether the temperatures of the droplet and the surface or the temperature difference between the two dominate the anti-/de-icing performance. Herein, this scientific question is experimentally studied based on the mobility of a water droplet over a superhydrophobic coating. The mobility is characterized by the sliding angle between the droplet and the coating surface. It was found that the temperature difference between the droplet and the coating surface has a higher impact on the sliding angle than their individual temperatures.


2018 ◽  
Vol 13 (8) ◽  
pp. 1159-1164
Author(s):  
Jing Li ◽  
Fengyu Fan ◽  
Qiang Li ◽  
Feng Du ◽  
Huadong Yu

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 253-262 ◽  
Author(s):  
ERIK BOHLIN ◽  
CAISA JOHANNSON ◽  
MAGNUS LESTELIUS

The effect of coating structure variations on flexographic print quality was studied using pilot-coated paperboard samples with different latex content and latex particle sizes. Two latexes, with particle sizes of 120 nm and 160 nm, were added at either 12 parts per hundred (pph) or 18 pph to the coating formulation. The samples were printed with full tone areas at print forces of 25 N and 50 N in a laboratory flexographic printing press using a waterbased ink. A high ratio of uncovered areas (UCAs) could be detected for the samples that contained 18 pph latex printed at a print force of 25 N. UCAs decreased with increased print force and with decreased amounts of latex in the coating formulation. The fraction of latex covered area on the coating surface was estimated to be 0.35–0.40 for the 12 pph, and 0.70–0.75 for the 18 pph samples. The ink penetration depth into the coating layer could be linked to the fraction of latex-free areas on the coating surface. Optical cross section microscopy indicated that a higher printing force did not increase the depth of penetrated ink to any greater extent. Higher printing force did increase contact between plate and substrate, leading to an improved distribution of the ink. This, in turn, increased print density and decreased UCAs. On closer inspection, the UCAs could be categorized as being induced by steep topographic changes. When appearing at other locations, they were more likely to be caused by poor wetting of the surface. To understand the wetting behavior of the coating surface, observed contact angles were compared with calculated contact angles on surfaces of mixed composition.


2020 ◽  
Vol 12 (2) ◽  
pp. 02023-1-02023-4
Author(s):  
Sanjay S. Latthe ◽  
◽  
Rajaram S. Sutar ◽  
A. K. Bhosale ◽  
Vishnu S. Kodag ◽  
...  

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