Effect of a liquid flow on the forces between charged solid surfaces and the non-equilibrium electric double layer

Area of Science:

• Physical Chemistry
• Surface Science
• Fluid Dynamics

Background:

• Fluid properties change in confined charged areas, influencing transport.
• Electrical double layer (EDL) dynamics near charged surfaces are critical.
• Limited research exists on non-equilibrium EDL and surface forces during flow.

Purpose of the Study:

• To review how liquid flow affects the EDL and surface forces on charged hydrophilic surfaces.
• To consolidate findings from molecular dynamics (MD) simulations and surface force experiments.
• To highlight the impact of flow on non-equilibrium EDL and associated forces.

Main Methods:

• Review of existing molecular dynamics (MD) simulations.
• Analysis of surface force experimental data.
• Focus on charged hydrophilic solid surfaces in aqueous electrolyte solutions.

Main Results:

• Liquid flow distorts the EDL, altering surface forces.
• Factors influencing EDL and forces include surface charge, ion properties, concentration, and flow rate.
• Fluid viscosity near surfaces increases with flow; counterion adsorption affects flow direction.

Conclusions:

• Liquid flow significantly modifies EDL structure and surface forces.
• Hydrodynamic and electrostatic forces change dynamically with flow.
• Understanding these non-equilibrium effects is crucial for applications involving controlled fluid transport in charged channels.