scholarly journals Electroosmosis as a probe for electrostatic correlations

Soft Matter ◽  
2020 ◽  
Vol 16 (47) ◽  
pp. 10688-10696
Author(s):  
Ivan Palaia ◽  
Igor M. Telles ◽  
Alexandre P. dos Santos ◽  
Emmanuel Trizac
Keyword(s):  
Surface Charge ◽  
Electroosmotic Flow ◽  
Channel Surface ◽  
Electrostatic Coupling

Ionic correlations affect electroosmosis in planar salt-free channels. Electroosmotic flow can then be used as a calibrated measurement of electrostatic coupling and channel surface charge.

Molecular Dynamics Simulation of Electroosmotic Flow in Nanotubes

2007 ◽  
Author(s):  
Yunfei Chen ◽  
Zhonghua Ni ◽  
Guiming Wang ◽  
Dongyan Xu ◽  
Deyu Li
Keyword(s):  
Molecular Dynamics ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Electroosmotic Flow ◽  
Continuum Theory ◽  
Ion Distribution ◽  
Charge Inversion ◽  
Charge Densities ◽  
Simulation Results ◽  
The Continuum

The ion distribution and electroosmotic flow of sodium chloride solutions confined in cylindrical nanochannels with different surface charge densities are studied with molecular dynamics (MD). In order to obtain simulation results corresponding to more realistic situations, the MD simulation consists of two steps. The first step is used to equilibrate the system and obtain a more realistic ion distribution in the solution under different surface charge densities; and the second step is to apply an electrical field to drive the liquid and extract the electroosmotic flow information. Simulation results indicate that a higher surface-charge density corresponds to a higher peak of the counter ion concentration. Predictions based on the continuum theory were also calculated and compared with the molecular dynamics results. Even though the continuum theory cannot reflect the molecular nature of ions and water molecules, it is found that for low surface charge densities, the continuum theory can still give reasonable results if modified boundary conditions are applied. Charge inversion under high surface charge density has been predicted and observed recently, however, the simulation results do not indicate charge inversion even for a surface density as high as −0.34 C/m2. This might be due to the fact that we perform the MD simulations with monovalent ions, which have a tendency to suppress charge inversion, as demonstrated in the recent literature.

Thermal Effect on Electroosmotic Flow in a Slit Microchannel

2013 ◽  
Author(s):  
Yi Zhou ◽  
Chun Yang ◽  
Cunlu Zhao
Keyword(s):  
Boltzmann Equation ◽  
Charge Density ◽  
Surface Charge ◽  
Thermal Effect ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Ion Distribution ◽  
Temperature Dependent ◽  
Constant Potential ◽  
Constant Charge

Electroosmotic flow (EOF) in microfluidic systems is frequently subjected to thermal effect because of temperature-dependent material properties. Boltzmann equation is usually used to describe the ion distribution in EOF. This study will compare the ion distribution under the thermal effect with the Boltzmann distribution. Moreover, for thin electrical double layer (EDL), constant potential model always be used to simplify the calculation of EOF at constant charge. In this study, the thermal effects on EOF at both constant potential and constant charge are analyzed. In addition, as the surface charge density increases largely with higher temperature, in this study efforts are also made to address the thermal effect on EOF induced by the temperature-dependent charge density. In particular, a numerical model is presented for investigating the steady EOF under the thermal effect. The proposed model involves several coupled governing equations including the Nernst-Planck equations, the Poisson equation, the modified Navier-Stokes equations, and the energy equation. The simulation results show that the Boltzmann equation cannot fully describe the ionic concentration distributions under the large thermal effect when EDL overlap. Moreover, for thin EDL, the electroosmotic velocity under the thermal effect at constant potential is lower than that at constant charge, due to the negative electrothermal force at constant potential. Furthermore, it is revealed that the temperature-dependence of surface charge can significantly modify the characteristics of EOF.

Fluid Flow in Nanometer Scale Channels: Effects of Polymer Coating

2006 ◽  
Author(s):  
R. Qiao ◽  
P. He
Keyword(s):  
Atomistic Simulation ◽  
Electroosmotic Flow ◽  
Transport Mechanism ◽  
Fluid Transport ◽  
Flow Regulation ◽  
Nanometer Scale ◽  
Fundamental Understanding ◽  
Channel Surface ◽  
Polymer Type ◽  
Fundamental Mechanism

Electroosmotic flow is one of the most important fluid transport mechanism in nanofluidic systems due to its ease-of-control and excellent scaling behavior. In this paper, we report on the atomistic simulation of electroosmotic flow regulation by coating the channel surface with a thin layer of polymers. While such coating is applied routinely in practice, the fundamental mechanism of the flow control is not well-understood. We show that the flow depends both on the polymer type and coating density. A detailed analysis of these results indicates that the flow regulation has both a hydrodynamic origin and a physio-chemical origin. The results highlight the need to integrate physical chemistry into the fluid mechanics for a fundamental understanding of the fluid transport at nanoscale.

Surface charge-dependent hydrodynamic properties of an electroosmotic slip flow

2018 ◽  
Vol 20 (48) ◽  
pp. 30365-30375 ◽  
Author(s):  
Majid Rezaei ◽  
Ahmad Reza Azimian ◽  
Ahmad Reza Pishevar
Keyword(s):  
Surface Charge ◽  
Electroosmotic Flow ◽  
Slip Flow ◽  
Solid Surfaces ◽  
General View ◽  
Hydrodynamic Properties

The present paper provides a general view of the charge-dependent electroosmotic flow slippage over hydrophobic solid surfaces.

Decorating surface charge of graphite nanoplate using an electrostatic coupling agent for 3‐dimensional polymer nanocomposite

2019 ◽  
Vol 137 (8) ◽  
pp. 48390
Author(s):  
Seung Han Ryu ◽  
Seil Kim ◽  
Young‐Tae Kwon ◽  
Young Ki Park ◽  
Sung‐Oong Kang ◽  
...  
Keyword(s):  
Surface Charge ◽  
Coupling Agent ◽  
Polymer Nanocomposite ◽  
3 Dimensional ◽  
Electrostatic Coupling

Electroosmotic Flow in Nanotubes with High Surface Charge Densities

Nano Letters ◽  
2007 ◽  
Vol 8 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Yunfei Chen ◽  
Zhonghua Ni ◽  
Guiming Wang ◽  
Dongyan Xu ◽  
Deyu Li
Keyword(s):  
Surface Charge ◽  
Electroosmotic Flow ◽  
High Surface ◽  
Charge Densities

scholarly journals Oxaliplatin neurotoxicity – no general ion channel surface-charge effect

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Amir Broomand ◽  
Elin Jerremalm ◽  
Jeffrey Yachnin ◽  
Hans Ehrsson ◽  
Fredrik Elinder
Keyword(s):  
Ion Channel ◽  
Surface Charge ◽  
Charge Effect ◽  
Channel Surface ◽  
Surface Charge Effect

scholarly journals Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels

The Analyst ◽  
2015 ◽  
Vol 140 (1) ◽  
pp. 113-126 ◽  
Author(s):  
Franklin I. Uba ◽  
Swathi R. Pullagurla ◽  
Nichanun Sirasunthorn ◽  
Jiahao Wu ◽  
Sunggook Park ◽  
...  
Keyword(s):  
Surface Modification ◽  
Zeta Potential ◽  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Electroosmotic Flow ◽  
Chemically Modified

We report the surface modification of thermoplastic nanochannels and the evaluation of the surface charge density, zeta potential and electroosmotic flow (EOF).

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