Wall embedded electrodes to modify electroosmotic flow in silica nanoslits

Area of Science:

• Physical Chemistry
• Surface Science
• Nanofluidics

Background:

• Electrical double layer phenomena are critical in nanoconfined systems.
• Nonuniform surface charge density significantly impacts electroosmotic flow (EOF).
• Controlling EOF is essential for microfluidic and nanofluidic applications.

Purpose of the Study:

• To investigate the control of electroosmotic flow in a silica nanoslit.
• To explore the effect of patterned surface potential on EOF.
• To provide physical insight into manipulating electrokinetic transport.

Main Methods:

• Utilizing extensive (160 ns) nonequilibrium molecular dynamics (NEMD) simulations.
• Implementing embedded charged electrodes within a channel wall to modify surface charge.
• Analyzing ion redistribution and resulting flow dynamics.

Main Results:

• Patterned surface potential effectively alters electroosmotic flow rates.
• Embedded electrodes induce significant changes in ion distribution.
• Observed alterations in EOF driving force and velocity profiles, including local flow reversal.

Conclusions:

• Surface charge patterning offers a viable method for electrokinetic flow control in nanoslits.
• This approach enables precise manipulation of fluid dynamics at the nanoscale.
• The findings contribute to a deeper understanding of electrokinetic phenomena in confined environments.