Instability and self-propulsion of flexible autophoretic filaments

Fuente: arXiv
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Main Authors: Makanga, Ursy, Varma, Akhil, Katsamba, Panayiota
Format: Preprint
Published: 2025
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author Makanga, Ursy
Varma, Akhil
Katsamba, Panayiota
author_facet Makanga, Ursy
Varma, Akhil
Katsamba, Panayiota
contents Over the past decade, autophoretic colloids have emerged as a prototypical system for studying self-propelled motion at microscopic scales, with promising applications in microfluidics, micromachinery, and therapeutics. Their motion in a viscous fluid hinges on their ability to induce surface slip flows that are spatially asymmetric from self-generated solute gradients. Here, we demonstrate theoretically that a straight elastic filament with homogeneous surface chemical properties -- which is otherwise immotile -- can spontaneously achieve self-propulsion by experiencing a buckling instability that serves as the symmetry-breaking mechanism. Using efficient numerical simulations, we characterize the nonlinear dynamics of the elastic filament and show that, over time, it attains distinct swimming modes such as a steadily translating "U" shape and a metastable rotating "S" shape when semiflexible, and an oscillatory state when highly flexible. Our findings provide physical insight into future experiments and the design of reconfigurable synthetic active colloids.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10153
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Instability and self-propulsion of flexible autophoretic filaments
Makanga, Ursy
Varma, Akhil
Katsamba, Panayiota
Soft Condensed Matter
Fluid Dynamics
Over the past decade, autophoretic colloids have emerged as a prototypical system for studying self-propelled motion at microscopic scales, with promising applications in microfluidics, micromachinery, and therapeutics. Their motion in a viscous fluid hinges on their ability to induce surface slip flows that are spatially asymmetric from self-generated solute gradients. Here, we demonstrate theoretically that a straight elastic filament with homogeneous surface chemical properties -- which is otherwise immotile -- can spontaneously achieve self-propulsion by experiencing a buckling instability that serves as the symmetry-breaking mechanism. Using efficient numerical simulations, we characterize the nonlinear dynamics of the elastic filament and show that, over time, it attains distinct swimming modes such as a steadily translating "U" shape and a metastable rotating "S" shape when semiflexible, and an oscillatory state when highly flexible. Our findings provide physical insight into future experiments and the design of reconfigurable synthetic active colloids.
title Instability and self-propulsion of flexible autophoretic filaments
topic Soft Condensed Matter
Fluid Dynamics
url https://arxiv.org/abs/2509.10153