Electro-wetting of a nanoscale water droplet on a polar solid surface in electric fields

2018 ◽  
Vol 20 (17) ◽  
pp. 11987-11993 ◽  
Author(s):  
Fenhong Song ◽  
Long Ma ◽  
Jing Fan ◽  
Qicheng Chen ◽  
Guangping Lei ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Solid Surface ◽  
Water Droplet ◽  
Water Molecules ◽  
Polar Surface ◽  
Electro Wetting

Water molecules interact with a polar surface in an electric field to realign their point dipoles, which determine the spreading behaviors of the droplets.

Molecular Dynamics Simulation of Electrically-Assisted Spreading of an Ionically Conducting Water Droplet

2013 ◽  
Author(s):  
Fenhong Song ◽  
Ben Q. Li ◽  
Chao Liu
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Solid Surface ◽  
Water Droplet ◽  
Negative Ions ◽  
Ion Concentration ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Pure Liquid ◽  
Freely Moving

Molecular dynamics simulations are performed to study the spreading behavior of a nanosized water droplet that contains freely moving ions subject to an imposed electric field parallel to a solid surface. Results show that positive and negative ions respond to the applied electric field in a different manner, whereas water molecules are polarized by realigning themselves in the electric field. These localized behaviors of the ions and polarized molecules define the droplet deformation and spreading on a solid substrate. Both the ion concentration and the strength of the applied field play an important role in re-alignment of the polarized water molecules and in the movement of ions. The existence of the freely moving ions causes the droplet to spread differently from the pure liquid. It is observed that an ionically conducting water droplet undergoes the asymmetric-to-symmetric spreading transition at about the field strength of 0.05V/Å, which is considerably smaller than the same sized water droplet without ions. Also, the ionically conducting droplet completely wets the solid surface in the presence of a strong electric field.

Modeling the Effect of External Electric Fields on the Dynamics of a Confined Water Nano-Droplet

2021 ◽  
Vol 67 ◽  
pp. 89-96
Author(s):  
Mahboubeh Kargar ◽  
Amir Lohrasebi
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
External Electric Field ◽  
Electric Fields ◽  
Water Droplet ◽  
Water Molecules ◽  
Confined Water ◽  
External Electric Fields ◽  
Water Filters ◽  
Dynamics Method

The effects of the application of constant electric fields on the dynamics of a confined water droplet between two different surfaces are investigated, by using a molecular dynamics method. It is found that the water molecules responded to the electric field, which partially depends on the wettability of the different surfaces. The results reveal that the application of external electric fields causes to create extra pressure on the surfaces, which are theoretically justified. The induced pressure could be experienced by multilayer nano-filters, which are used in desalination processes, with the aid of an external electric field, and may reduce the water filters shelf life.

scholarly journals The Variation of Factor of Enhancement in Nucleation Rate with Electric Field for Water Vapour and Ice

2020 ◽  
Vol 10 (2) ◽  
pp. 221-223
Keyword(s):  
Electric Field ◽  
Water Vapour ◽  
Electric Fields ◽  
Nucleation Rate ◽  
Water Molecules ◽  
Saturation Ratio

the nucleation rate is the parameter to judge the effect of electric field on nucleation of water vapour and ice glaciation. In the presence of electric field the total nucleation is the sum of nucleation due to electric field and nucleation due to diffusion of water molecules. Thus we can say the nucleation rate is enhanced by the factor of RE. This is known as factor of enhancement in nucleation rate. In the present work we will calculate the factor of enhancement in nucleation rate for water vapour and ice on temperature 268 K at different electric fields as a function of super saturation ratio.

scholarly journals Origin of the enhanced structural and reorientational relaxation rates in the presence of relatively weak dc electric fields

2004 ◽  
Vol 76 (1) ◽  
pp. 215-221 ◽  
Author(s):  
A. Vegiri
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Electric Fields ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Common Mechanism ◽  
Weak Electric Field ◽  
Water Molecules ◽  
Relaxation Rates ◽  
Dynamics Simulations

The origin of the dramatic increase of the reorientational and structural relaxation rates of single water molecules in clusters of size N = 16, 32, and 64 at T = 200 K, under the influence of an external, relatively weak electric field (~0.5 107 V/cm) is examined through molecular dynamics simulations. The observed effect is attributed not to any profound structural changes, but to the increase of the size of the molecular cage. The response of water to an electric field in this range shows many similarities with the dynamics of water under low pressure. By referring to simulations and experiments from the literature, we show that in both cases the observed effects are dictated by a common mechanism.

scholarly journals Separation of water–ethanol solutions with carbon nanotubes and electric fields

2016 ◽  
Vol 18 (48) ◽  
pp. 33310-33319 ◽  
Author(s):  
Winarto Winarto ◽  
Daisuke Takaiwa ◽  
Eiji Yamamoto ◽  
Kenji Yasuoka
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Electric Fields ◽  
Electrostatic Interactions ◽  
Water Molecules ◽  
Ordered Structure

Under an electric field, water prefers to fill CNTs over ethanol, and electrostatic interactions within the ordered structure of the water molecules determine the separation effects.

scholarly journals Can Electric Fields Drive Chemistry for an Aqueous Microdroplet?

2021 ◽  
Author(s):  
Hongxia Hao ◽  
Itai Leven ◽  
Teresa Head-Gordon
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Water Droplet ◽  
Reaction Rates ◽  
Surface Reactivity ◽  
Bulk Solution ◽  
Excess Charge ◽  
Electronic Effects ◽  
Rate Acceleration

Abstract Reaction rates of common organic reactions have been reported to increase by one to six orders of magnitude in aqueous microdroplets compared to bulk solution, but the reasons for the rate acceleration are poorly understood. We investigate the role of electric fields at water droplet surfaces that might explain the promotion of unusual reactive chemistry, along with changes in electric field profiles as a function of excess charge to model the electrospray fragmentation process. We find that electric field alignments along free O-H bonds at the surface yield field strength distributions that are ~30 MV/cm larger on average than that found for O-H bonds in the interior of the water droplet, consistent with greater surface reactivity. We emphasize the importance of both nuclear and electronic effects at the surface, and the non-linear coupling of intramolecular solute polarization with intermolecular solvent modes, as a necessary feature for predicting the higher field strengths at water droplet surfaces.

Dielectrophoretic Control of a Droplet at the Interface of Two Liquids in a Three Liquid System

2018 ◽  
Author(s):  
Manoj Lokanathan ◽  
Enakshi Wikramanayake ◽  
Vaibhav Bahadur ◽  
Roger Bonnecaze
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Threshold Voltage ◽  
Water Droplet ◽  
Critical Size ◽  
Silicone Oil ◽  
Liquid System ◽  
Interfacial Phenomena ◽  
Immiscible Liquids ◽  
Voltage Dependent

The influence of an electric field on a water droplet resting at the interface of two immiscible liquids is studied experimentally and theoretically. The droplet is initially in a state of equilibrium due to the balance between gravitational, buoyancy and capillary forces. Application of an electric field across the droplet-interface system disturbs the equilibrium. The electrical force increases the immersion angle of the droplet and eventually causes it to ‘sink’ when a critical immersion angle is reached. Experiments are conducted with a deionized water droplet, resting at the interface of silicone oil and sunflower oil. Experiments involve the application of an electric field and image analysis to track the voltage dependent immersion angle. The objective is to determine the threshold voltage at which the droplet sinks. Experiments are complemented by an analytical model that balances gravity, buoyancy, capillary, and dielectrophoretic forces to predict the change in the position of the droplet and the immersion angle. Experiments and analysis were conducted for Bond numbers ranging from 0.1 to 1.7, the latter being the critical size at which a droplet will ‘sink’ due to its weight. The predicted immersion angles and threshold voltage show a good match to the experimental measurements. Overall, this work highlights the utility of electric fields to control interfacial phenomena at the interface of two immiscible liquids.

Influences of electric fields on the operation of Aqy1 aquaporin channels: a molecular dynamics study

2020 ◽  
Vol 22 (44) ◽  
pp. 25859-25868
Author(s):  
Z. Rahimi ◽  
A. Lohrasebi
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
External Electric Field ◽  
Electric Fields ◽  
Md Simulation ◽  
Simulation Method ◽  
Water Molecules ◽  
Aquaporin Channels

The effects of application of external electric field on the dynamics of water molecules inside an Aquaporin channel, embedded within a stochastically fluctuating membrane, was modeled by means of the application of the molecular dynamics (MD) simulation method.

Structures of Water Molecules in Carbon Nanotubes Induced with Electric Fields and its Application for Water-Methanol Separation

2016 ◽  
Vol 842 ◽  
pp. 453-456 ◽  
Author(s):  
Winarto ◽  
Daisuke Takaiwa ◽  
Eiji Yamamoto ◽  
Kenji Yasuoka
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Electric Field ◽  
Electric Fields ◽  
Electrostatic Interaction ◽  
Water Molecules ◽  
Ordered Structures ◽  
Separation Effect ◽  
Wide Range ◽  
Dynamics Simulations

Water confined in carbon nanotubes (CNTs) under the influence of an electric field has interesting properties that are potential for nanofluidic-based applications. With molecular dynamics simulations, this work shows that the electric field induces formation of ordered structures of water molecules in the CNTs. Formation of the ordered structures strengthens the electrostatic interaction between the water molecules. As a result, water strongly prefers to fill CNTs over methanol and it produces a separation effect. Interestingly, the separation effect with the electric field does not decrease for a wide range of CNT diameter.

Molecular dynamics simulations of electric field induced water flow inside a carbon nanotorus: a molecular cyclotron

2017 ◽  
Vol 19 (19) ◽  
pp. 12384-12393 ◽  
Author(s):  
Hassan Sabzyan ◽  
Maryam Kowsar
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Molecular Dynamics Simulations ◽  
Water Flow ◽  
Electric Fields ◽  
Water Molecules ◽  
Dynamics Simulations

A nano-flow is induced by applying gigahertz rotating electric fields (EFs) of different strengths and frequencies on a carbon nanotorus filled with water molecules, using molecular dynamics simulations.

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