Streaming Current for Surfaces Covered by Square and Hexagonal Monolayers of Spherical Particles

Area of Science:

• Colloid and Surface Science
• Electrokinetics
• Computational Fluid Dynamics

Background:

• Streaming current measurements are sensitive to surface properties.
• Understanding particle coverage on substrates is crucial for various applications.
• Hydrodynamic interactions and charge transport influence streaming current.

Purpose of the Study:

• To theoretically evaluate interface and particle contributions to streaming current.
• To develop fitting functions for approximating numerical results.
• To assess the utility of streaming current measurements for determining particle coverage.

Main Methods:

• Theoretical evaluation of streaming current for ordered and random particle arrangements.
• Approximation of numerical results using fitting functions with exponential and linear terms.
• Analysis of hydrodynamic screening and charge convection effects.

Main Results:

• Streaming currents for ordered and random arrangements differ within experimental error.
• Fitting functions accurately approximate numerical results.
• Roughness can reduce streaming current by over 30% for equal zeta potentials.

Conclusions:

• Streaming current measurements, combined with fitting functions, offer a convenient method for evaluating particle coverage.
• Detailed knowledge of particle distribution is not always necessary.
• Surface roughness significantly impacts streaming current, highlighting its importance in electrokinetic phenomena.