Electrophoretic motion of hydrophobic spherical particles in nanopore: Characteristics, separation, and resistive pulse sensing

Electrophoretic motion of hydrophobic particles has been scrutinized numerically in solid-state nanopores. The Poisson, Stokes, and Nernst-Planck equations are solved simultaneously, and the Newton-Raphson algorithm is used to compute the correct velocity at each point. For the hydrophobic surface characterization, the Navier-slip boundary condition with a wide range of slip lengths is applied to the nanoparticle's surface. The effects of the electric field intensity, the electrolyte concentration, and the particle's size on the electrophoretic velocity are examined. Then, the nanopore's size and surface charge density are manipulated to achieve the configuration for separating hydrophobic and hydrophilic particles based on their slip lengths. The results show that the hydrophobic and hydrophilic particles, under particular circumstances, would move in the opposite direction in a nanopore. Finally, the resistive pulses of the particles with various slip lengths are studied. The resistive pulse properties of the hydrophobic and the hydrophilic particles are completely distinguishable and show potential application for resistive pulse sensing as a tool for reckoning the particle's slip length.

Automated summary

The electrophoretic motion of hydrophobic particles in solid-state nanopores is numerically investigated. The Poisson, Stokes, and Nernst-Planck equations are simultaneously solved using the Newton-Raphson algorithm. The hydrophobic surface characteristics are described using the Navier-slip boundary condition with a wide range of slip lengths. The study examines the effects of electric field intensity, electrolyte concentration, and particle size on electrophoretic velocity, and manipulates the nanopore's size and surface charge density to separate hydrophobic and hydrophilic particles based on their slip lengths. The resistive pulse properties of particles with different slip lengths are also studied, showing potential application for resistive pulse sensing to determine particle slip length.