Controlling states of water droplets on nanostructured surfaces by design

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18240-18245 ◽  
Author(s):  
Chongqin Zhu ◽  
Yurui Gao ◽  
Yingying Huang ◽  
Hui Li ◽  
Sheng Meng ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Droplets ◽  
Nanostructured Surfaces ◽  
Base Angle ◽  
Intrinsic Contact Angle

The transition between the Cassie and Wenzel states can be controlled via precisely designed trapezoidal nanostructures on the surface, for which the base angle of the trapezoids and the intrinsic contact angle of the surface are two possible adjustable parameters.

Synthesis of Superhydrophobic Carbon Surface during Combustion Propane

2011 ◽  
Vol 14 (1) ◽  
pp. 19 ◽  
Author(s):  
Z.A. Mansurov ◽  
M. Nazhipkyzy ◽  
B.T. Lesbayev ◽  
N.G. Prikhodko ◽  
M. Auyelkhankyzy ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Morphology ◽  
Carbon Nanostructures ◽  
Carbon Surface ◽  
Flame Synthesis ◽  
Water Droplets ◽  
Sem Images ◽  
Surface Carbon ◽  
Nanostructured Surfaces ◽  
Nonpremixed Flame

We synthesize and deposit carbon nanostructures through flame synthesis on silicon and nickel wafers at different nonpremixed flame locations to produce hydrophobic surfaces. The hydrophobicity is characterized through the contact angle for water droplets placed on the surface. The surface morphology of the nanoparticles is obtained from SEM images. The morphology and hydrohobicity of the nanostructured surfaces depends upon the deposition, which differs at various flame locations. We determine the optimum flame location for the synthesis and deposition of surface carbon nanostructures that lead to maximum hydrophobicity.

Magnetically Induced Decrease in Droplet Contact Angle on Nanostructured Surfaces

Langmuir ◽  
2011 ◽  
Vol 27 (19) ◽  
pp. 11747-11751 ◽  
Author(s):  
Qian Zhou ◽  
William D. Ristenpart ◽  
Pieter Stroeve
Keyword(s):  
Contact Angle ◽  
Nanostructured Surfaces

Light-driven motion of water droplets with directional control on nanostructured surfaces

Nanoscale ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 4295-4301 ◽  
Author(s):  
Shun An ◽  
Mingyuan Zhu ◽  
Kan Gu ◽  
Modi Jiang ◽  
Qingchen Shen ◽  
...  
Keyword(s):  
Water Droplets ◽  
Nanostructured Surfaces ◽  
Directional Control ◽  
Droplet Transport

Discrete droplet transport has drawn much interest in a broad range of applications.

scholarly journals Bacteria Death and Osteoblast Metabolic Activity Correlated to Hydrothermally Synthesised TiO2 Surface Properties

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1201 ◽  
Author(s):  
Alka Jaggessar ◽  
Asha Mathew ◽  
Tuquabo Tesfamichael ◽  
Hongxia Wang ◽  
Cheng Yan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Metabolic Activity ◽  
Mechanical Stability ◽  
Antibacterial Properties ◽  
Mechanical Tests ◽  
Nanostructured Surfaces ◽  
Surface Contact Angle ◽  
Cellular Metabolic Activity ◽  
Structure Height

Orthopaedic surgery comes with an inherent risk of bacterial infection, prolonged antibiotic therapy and revision surgery. Recent research has focused on nanostructured surfaces to improve the bactericidal and osseointegrational properties of implants. However, an understanding of the mechanical properties of bactericidal materials is lacking. In this work, the surface properties of hydrothermal TiO2 nanostructured surfaces are investigated for their effect on bactericidal efficiency and cellular metabolic activity of human osteoblast cells. TiO2 nanostructures, approximately 307 nm in height and 14 GPa stiffness, were the most effective structures against both gram-positive (Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacteria. Statistical analysis significantly correlated structure height to the death of both bacteria strains. In addition, the surface contact angle and Young’s modulus were correlated to osteoblast metabolic activity. Hydrophilic surfaces with a contact angle between 35 and 50° produced the highest cellular metabolic activity rates after 24 hours of incubation. The mechanical tests showed that nanostructures retain their mechanical stability and integrity over a long time-period, reaffirming the surfaces’ applicability for implants. This work provides a thorough examination of the surface, mechanical and wettability properties of multifunctional hydrothermally synthesised nanostructured materials, capable of killing bacteria whilst improving osteoblast metabolic rates, leading to improved osseointegration and antibacterial properties of orthopaedic implants.

Investigation of Pool Boiling Critical Heat Flux Enhancement on a Modified Surface Through the Dynamic Wetting of Water Droplets

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Ho Seon Ahn ◽  
Joonwon Kim ◽  
Moo Hwan Kim
Keyword(s):  
Surface Tension ◽  
Heat Flux ◽  
Contact Angle ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
Water Layer ◽  
Contact Angles ◽  
Water Droplets ◽  
Dynamic Wetting ◽  
Modified Surface

Dynamic wetting behaviors of water droplet on the modified surface were investigated experimentally. Dynamic contact angles were measured as a characterization method to explain the extraordinary pool boiling critical heat flux (CHF) enhancement on the zirconium surface by anodic oxidation modification. The sample surface is rectangular zirconium alloy plates (20 × 25 × 0.7 mm), and 12 μl of deionized water droplets were fallen from 40 mm of height over the surface. Dynamic wetting movement of water on the surface showed different characteristics depending on static contact angle (49.3 deg–0 deg) and surface temperature (120 °C–280 °C). Compared with bare surface, wettable and spreading surface had no-receding contact angle jump and seemed stable evaporating meniscus of liquid droplet in dynamic wetting condition on hot surface. This phenomenon could be explained by the interaction between the evaporation recoil and the surface tension forces. The surface tension force increased by micro/nanostructure of the modified zirconium surface suppresses the vapor recoil force by evaporation which makes the water layer unstable on the heated surface. Thus, such increased surface force could sustain the water layer stable in pool boiling CHF condition so that the extraordinary CHF enhancement could be possible.

Temperature-Dependent Wettability of Water on a Nickel Surface at Pressurized Condition: A Molecular Dynamics Study

2019 ◽  
Author(s):  
Dong-Lei Zeng ◽  
Biao Feng ◽  
Jia-Wen Song ◽  
Li-Wu Fan
Keyword(s):  
Contact Angle ◽  
Hydrogen Bonds ◽  
Average Energy ◽  
Contact Angles ◽  
Nickel Surface ◽  
Free Energies ◽  
Water Droplets ◽  
Temperature Dependent ◽  
Interfacial Free Energies ◽  
Solid Liquid

Abstract Temperature-dependent wettability of water droplets on a metal surface in a pressurized environment is of great theoretical and practical significance. In this paper, molecular dynamic simulation is used to study this problem by relating the temperature-dependent apparent contact angles to the changes in solid-liquid and solid-vapor interfacial free energies and hydrogen bonds in the nano-sized water droplets with increasing the temperature. The temperature range of interest is set from 298 K to 538 K in a 20 K interval under a constant pressure of 7 MPa. The results show that the contact angle in general decreases with raising the temperature and decreasing trend can be divided into two sections with different slopes. The contact angle drops slowly when the temperature is below 458 K as a critical point. Beyond this point, the contact angle shows a much steeper decrease. The difference between solid-vapor and solid-liquid interfacial free energies is found to decrease slightly with temperature. Combining with that the surface tension drops with increasing the temperature, a decreasing trend of the contact angle is expected according to the Young’s equation. As the temperature increases, the number and average energy of the hydrogen bonds both decrease, and the hydrogen bonds tend to aggregate at the bottom of the nano-droplets.

Molecular Simulation of the Contact Angle of Water Droplet on a Platinum Surface

2005 ◽  
Author(s):  
Bo Shi ◽  
Shashank Sinha ◽  
Vijay K. Dhir
Keyword(s):  
Contact Angle ◽  
Molecular Simulation ◽  
Simulation Study ◽  
Water Droplet ◽  
Solid Wall ◽  
Contact Angles ◽  
Water Droplets ◽  
Platinum Surface

This paper presents a molecular simulation study of the contact angles of water droplets on a platinum surface for a range of temperatures. SPC/E and Z-P model are used for the water-water and water-platinum potentials, respectively. The results show that the contact angle decreases with the increase of system temperatures and increases when the potential decreases. When the temperature is high enough, the contact angles drop to zero degrees. The results were compared with the argon-virtual solid wall and water-Aluminum results, a similar trend was found.

scholarly journals Water droplet friction and rolling dynamics on superhydrophobic surfaces

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Matilda Backholm ◽  
Daniel Molpeceres ◽  
Maja Vuckovac ◽  
Heikki Nurmi ◽  
Matti J. Hokkanen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Friction Force ◽  
Water Droplet ◽  
Superhydrophobic Surfaces ◽  
Silicon Surfaces ◽  
Force Sensors ◽  
Water Droplets ◽  
Indirect Contact ◽  
Gold Standard Method ◽  
Superhydrophobic Coatings

Abstract Superhydrophobicity is a remarkable surface property found in nature and mimicked in many engineering applications, including anti-wetting, anti-fogging, and anti-fouling coatings. As synthetic superhydrophobic coatings approach the extreme non-wetting limit, quantification of their slipperiness becomes increasingly challenging: although contact angle goniometry remains widely used as the gold standard method, it has proven insufficient. Here, micropipette force sensors are used to directly measure the friction force of water droplets moving on super-slippery superhydrophobic surfaces that cannot be quantified with contact angle goniometry. Superhydrophobic etched silicon surfaces with tunable slipperiness are investigated as model samples. Micropipette force sensors render up to three orders of magnitude better force sensitivity than using the indirect contact angle goniometry approach. We directly measure a friction force as low as 7 ± 4 nN for a millimetric water droplet moving on the most slippery surface. Finally, we combine micropipette force sensors with particle image velocimetry and reveal purely rolling water droplets on superhydrophobic surfaces.

Contact Angle of Water Droplets in High Temperature and High Pressure environment

2003 ◽  
Vol 2003.3 (0) ◽  
pp. 265-266
Author(s):  
Naohisa TAMURA ◽  
Norihiro FUKAMACHI ◽  
Tatsuya HAZUKU ◽  
Tomoji TAKAMASA ◽  
Kenrou TAKAMORI
Keyword(s):  
Contact Angle ◽  
High Pressure ◽  
High Temperature ◽  
Water Droplets ◽  
High Pressure Environment
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