Active particle dynamics in uniform and patterned electroosmotic flows
Abstract
We investigate the dynamics of self-propelled spheroidal particles in electroosmotic channel flows generated by uniform, patterned, and combined zeta-potential distributions. The coupling between self-propulsion, particle shape, and electroosmotic advection gives rise to distinct regimes of confinement and transport. For a uniform zeta potential, the dynamics reduce to a two-dimensional system in cross-stream position and orientation. We show that this system possesses a non-canonical Hamiltonian structure, allowing its phase-space organization to be characterized analytically. For spherical particles, the dynamics admit a nonlinear-pendulum description, yielding the characteristic oscillation frequency and extent of the confined region. The oscillation frequency depends non-monotonically on electrostatic screening and reaches a maximum at an intermediate Debye parameter. Spatially patterned zeta potentials reorganize the dynamics by generating counter-rotating vortices and coupling streamwise position, cross-stream position, and particle orientation. Numerical simulations and dynamical-systems analysis reveal regimes of single-cell confinement and cross-cell migration, controlled by particle shape and electrostatic screening. When uniform and patterned components coexist, mean electroosmotic advection competes with vortex-induced recirculation, producing transport sensitive to particle shape and initial conditions. Together, these results connect Hamiltonian phase-space dynamics in uniform electroosmotic flow to vortex-mediated trapping and transport in patterned flows, highlighting the potential of surface electrostatic patterning to control particle motion without altering channel geometry.
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BibTeX
@misc{roy2026active,
title = {{Active particle dynamics in uniform and patterned electroosmotic flows}},
author = {Aritra Roy and Antarip Poddar and Rahil Valani},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00600},
eprint = {2611.00600},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00600},
}
RIS
TY - UNPB
TI - Active particle dynamics in uniform and patterned electroosmotic flows
AU - Aritra Roy
AU - Antarip Poddar
AU - Rahil Valani
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00600
UR - https://arxiv.org/abs/2611.00600
AB - We investigate the dynamics of self-propelled spheroidal particles in electroosmotic channel flows generated by uniform, patterned, and combined zeta-potential distributions. The coupling between self-propulsion, particle shape, and electroosmotic advection gives rise to distinct regimes of confinement and transport. For a uniform zeta potential, the dynamics reduce to a two-dimensional system in cross-stream position and orientation. We show that this system possesses a non-canonical Hamiltonian structure, allowing its phase-space organization to be characterized analytically. For spherical particles, the dynamics admit a nonlinear-pendulum description, yielding the characteristic oscillation frequency and extent of the confined region. The oscillation frequency depends non-monotonically on electrostatic screening and reaches a maximum at an intermediate Debye parameter. Spatially patterned zeta potentials reorganize the dynamics by generating counter-rotating vortices and coupling streamwise position, cross-stream position, and particle orientation. Numerical simulations and dynamical-systems analysis reveal regimes of single-cell confinement and cross-cell migration, controlled by particle shape and electrostatic screening. When uniform and patterned components coexist, mean electroosmotic advection competes with vortex-induced recirculation, producing transport sensitive to particle shape and initial conditions. Together, these results connect Hamiltonian phase-space dynamics in uniform electroosmotic flow to vortex-mediated trapping and transport in patterned flows, highlighting the potential of surface electrostatic patterning to control particle motion without altering channel geometry.
ER -