scholarly journals Dust removal from a hydrophobic surface by rolling fizzy water droplets

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 19811-19821 ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Saeed Bahatab ◽  
Ahmet Z. Sahin ◽  
...  
Keyword(s):  
Removal Rate ◽  
Hydrophobic Surface ◽  
Dust Removal ◽  
Liquid Droplets ◽  
Water Droplets

Here, environmental dust cleaning from an inclined hydrophobic surface by rolling liquid droplets has been studied and the influence of fluid droplets on the dust removal rate has been examined.

scholarly journals Heterogeneous freezing of water droplets containing kaolinite particles

2011 ◽  
Vol 11 (9) ◽  
pp. 4191-4207 ◽  
Author(s):  
B. J. Murray ◽  
S. L. Broadley ◽  
T. W. Wilson ◽  
J. D. Atkinson ◽  
R. H. Wills
Keyword(s):  
Cooling Rate ◽  
Surface Area ◽  
Clay Mineral ◽  
Constant Temperature ◽  
Hydrophobic Surface ◽  
Supercooled Liquid ◽  
Stochastic Approach ◽  
Solid Particles ◽  
Rate Coefficients ◽  
Water Droplets

Abstract. Clouds composed of both ice particles and supercooled liquid water droplets exist at temperatures above ~236 K. These mixed phase clouds, which strongly impact climate, are very sensitive to the presence of solid particles that can catalyse freezing. In this paper we describe experiments to determine the conditions at which the clay mineral kaolinite nucleates ice when immersed within water droplets. These are the first immersion mode experiments in which the ice nucleating ability of kaolinite has been determined as a function of clay surface area, cooling rate and also at constant temperatures. Water droplets containing a known amount of clay mineral were supported on a hydrophobic surface and cooled at rates of between 0.8 and 10 K min−1 or held at constant sub-zero temperatures. The time and temperature at which individual 10–50 μm diameter droplets froze were determined by optical microscopy. For a cooling rate of 10 K min−1, the median nucleation temperature of 10–40 μm diameter droplets increased from close to the homogeneous nucleation limit (236 K) to 240.8 ± 0.6 K as the concentration of kaolinite in the droplets was increased from 0.005 wt% to 1 wt%. This data shows that the probability of freezing scales with surface area of the kaolinite inclusions. We also show that at a constant temperature the number of liquid droplets decreases exponentially as they freeze over time. The constant cooling rate experiments are consistent with the stochastic, singular and modified singular descriptions of heterogeneous nucleation; however, freezing during cooling and at constant temperature can be reconciled best with the stochastic approach. We report temperature dependent nucleation rate coefficients (nucleation events per unit time per unit area) for kaolinite and present a general parameterisation for immersion nucleation which may be suitable for cloud modelling once nucleation by other important ice nucleating species is quantified in the future.

Fizzy water droplets levitate at room temperature

Physics World ◽  
2021 ◽  
Vol 34 (9) ◽  
pp. 7ii-7ii
Author(s):  
Isabelle Dumé
Keyword(s):  
Carbon Dioxide ◽  
Room Temperature ◽  
Deionized Water ◽  
Liquid Droplets ◽  
Water Droplets ◽  
Leidenfrost Effect ◽  
Gaseous Carbon Dioxide

Researchers have come up with a room-temperature way to recreate the Leidenfrost effect and levitate liquid droplets by pumping gaseous carbon dioxide into deionized water.

scholarly journals Bioinspired programmable wettability arrays for droplets manipulation

2020 ◽  
Vol 117 (9) ◽  
pp. 4527-4532 ◽  
Author(s):  
Lingyu Sun ◽  
Feika Bian ◽  
Yu Wang ◽  
Yuetong Wang ◽  
Xiaoxuan Zhang ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Near Infrared ◽  
Hydrophobic Surface ◽  
Transformation Property ◽  
Laboratory Research ◽  
Liquid Droplets ◽  
Energy Transformation ◽  
Droplet Transfer ◽  
Hydrophobic Property ◽  
Trimethylolpropane Triacrylate

The manipulation of liquid droplets demonstrates great importance in various areas from laboratory research to our daily life. Here, inspired by the unique microstructure of plant stomata, we present a surface with programmable wettability arrays for droplets manipulation. The substrate film of this surface is constructed by using a coaxial capillary microfluidics to emulsify and pack graphene oxide (GO) hybridN-isopropylacrylamide (NIPAM) hydrogel solution into silica nanoparticles-dispersed ethoxylated trimethylolpropane triacrylate (ETPTA) phase. Because of the distribution of the silica nanoparticles on the ETPTA interface, the outer surface of the film could achieve favorable hydrophobic property under selective fluorosilane decoration. Owing to the outstanding photothermal energy transformation property of the GO, the encapsulated hydrophilic hydrogel arrays could shrink back into the holes to expose their hydrophobic surface with near-infrared (NIR) irradiation; this imparts the composite film with remotely switchable surface droplet adhesion status. Based on this phenomenon, we have demonstrated controllable droplet sliding on programmable wettability pathways, together with effective droplet transfer for printing with mask integration, which remains difficult to realize by existing techniques.

Freezing of micrometer-sized liquid droplets of pure water evaporatively cooled in a vacuum

2018 ◽  
Vol 20 (45) ◽  
pp. 28435-28444 ◽  
Author(s):  
Kota Ando ◽  
Masashi Arakawa ◽  
Akira Terasaki
Keyword(s):  
Pure Water ◽  
Ice Nucleation ◽  
Nucleation Theory ◽  
Liquid Droplets ◽  
Freezing Time ◽  
Water Droplets

The freezing time of pure-water droplets is measured in a vacuum and simulated by ice nucleation theory.

The Collision Behavior of Droplets Splitted from a Droplet that Rebounded on Super-Hydrophobic Surface

2015 ◽  
Vol 723 ◽  
pp. 968-971 ◽  
Author(s):  
Zheng Yong Huang ◽  
Jian Li ◽  
Fei Peng Wang ◽  
Huan Huan Xia ◽  
Mao Chang Li
Keyword(s):  
Contact Time ◽  
Hydrophobic Surface ◽  
Reynolds Numbers ◽  
Elastic Collision ◽  
Water Droplets ◽  
Water Contact ◽  
Ice Accumulation ◽  
Pollution Flashover ◽  
Water Accumulation ◽  
Spreading Time

Droplet rebounding on super-hydrophobic surfaces is critical to suppress pollution flashover (i.e. enhancement of pollution flashover-voltage) and to reduce ice accumulation on insulators. This paper presents a novel way to reduce water accumulation on surface via the elastic collision between droplets splitted from a droplet that has rebounded from super-hydrophobic surface. The water-mass that contacted with surface will be reduced resultantly. The influence of hydrophobicity of the surface on contact time and spreading time of water droplets are discussed. The collision behavior between the splitted droplets is indicated by the surface charge that was induced by the rebounding droplets on super-hydrophobic surface. Experimental results show that the super-hydrophobic surface endows water droplets with shorter contact time, spreading time than those values obtained on a bare glass. Specific Web and Reynolds numbers can lead to the elastic rebounding between water droplets, delaying the water contact with the super-hydrophobic surface. The contact electrification between the rebounded droplet and the super-hydrophobic surface renders the droplet charged, thus determines the collision behavior of the splitted droplets that born from the rebounded droplet.

Study on Discharge of Separated Water Droplets in DC Field

2011 ◽  
Vol 130-134 ◽  
pp. 3276-3279
Author(s):  
Zong Xi Zhang ◽  
Shan Feng Yin
Keyword(s):  
Electric Field ◽  
Hydrophobic Surface ◽  
Electrical Equipment ◽  
Water Droplets ◽  
Surface Flashover ◽  
Voltage Drops ◽  
Flashover Voltage ◽  
Dc Electric Field ◽  
Water Drops ◽  
And Migration

With the accelerating construction of strong smart grid, and the grid voltage level rising, performance requirements for the electrical insulation of electrical equipment also continue to increase. In terms of the advantages of RTV on antifouling, RTV-based paints coated insulator coating capacity of its flash tolerance can significantly increase, mainly due to RTV coating hydrophobic hydrophobicity and migration. But when the hydrophobic surface is in the fully wet, many small drops of water in the surface will be gathered into big drops of water, and these large droplets will distort the surface electric field of the medium. So the flashover voltage of the hydrophobic surface’s separated water droplets under DC electric field are analyzed comparatively in this paper, while some influencing factors such as different medias and volume of water drops, are introduced in specific experiments, and their effects on the flashover voltage are analyzed; under DC electric field experiment on the surface of hydrophobic and hydrophilic surface flashover voltage drops separation characteristics were studied.

scholarly journals Facile construction of a polydopamine-based hydrophobic surface for protection of metals against corrosion

RSC Advances ◽  
2017 ◽  
Vol 7 (19) ◽  
pp. 11528-11536 ◽  
Author(s):  
Nan Wei ◽  
Yueyue Jiang ◽  
Ye Ying ◽  
Xiaoyu Guo ◽  
Yiping Wu ◽  
...  
Keyword(s):  
Metal Surfaces ◽  
Hydrophobic Surface ◽  
Water Droplets ◽  
Protection Of Metals

Metal surfaces with a hydrophobic feature, which could prevent percolation of water droplets and improve their capability against corrosion, arouse extensively interest.

scholarly journals Formation of double emulsion micro-droplets in a microfluidic device using a partially hydrophilic–hydrophobic surface

RSC Advances ◽  
2021 ◽  
Vol 11 (56) ◽  
pp. 35653-35662
Author(s):  
Ampol Kamnerdsook ◽  
Ekachai Juntasaro ◽  
Numfon Khemthongcharoen ◽  
Mayuree Chanasakulniyom ◽  
Witsaroot Sripumkhai ◽  
...  
Keyword(s):  
Flow Rate ◽  
Frequency Ratio ◽  
Encapsulation Efficiency ◽  
Double Emulsion ◽  
Hydrophobic Surface ◽  
Water Droplets ◽  
Oil In Water ◽  
Rate Ratios ◽  
Frequency Ratios ◽  
Ratio Range

(a) Droplet encapsulation efficiency & inner and outer diameters of water-in-oil-in-water droplets at various frequency ratios and flow rate ratios and (b) Images of water-in-oil-in-water droplets over a frequency-ratio range of fr = 0.73–1.30

scholarly journals Stretchable Hydrophobic Surfaces and Self-Cleaning Applications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Naser Al-Aqeeli ◽  
Abdullah Al-Sharafi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Droplet ◽  
Dust Removal ◽  
Dust Particles ◽  
Mass Ratio ◽  
Water Droplets ◽  
Surface Wetting ◽  
Hydrophobic Surfaces ◽  
Removal Mechanisms ◽  
Nano Size

Abstract Hydrophobizing of stretchable elastomer surfaces is considered and the reversible behavior of the resulting surface wetting state is examined after stretching and relaxing the hydrophobized samples. The environmental dust are analyzed in terms of elemental constitutes and size, and the dust pinning on the hydrophobized surface is measured. The dust removal mechanisms, by the water droplets on the hydrophobized surface, are investigated. We demonstrated that deposition of functionalized nano-size silica units on the elastomer surface gives rise to hydrophobicity with 135° ± 3° contact angle and low hysteresis of 3° ± 1°. Stretching hydrophobized elastomer surface by 50% (length) reduces the contact angle to 122° ± 3° and enhances the hysteresis to 6° ± 1°. However, relaxing the stretched sample causes exchanging surface wetting state reversibly. Water droplet rolling and sliding can clean the dusty hydrophobized surface almost 95% (mass ratio of the dust particles removed). Droplet puddling causes striations like structures along the droplet path and close examination of the few residues of the dust reveals that the droplet takes away considerably large amount of dust from surface.

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