Slender phoretic theory of chemically active filaments

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  • LadHyX, Ecole Polytechnique


Artificial microswimmers, or ‘microbots’, have the potential to revolutionise non-invasive medicine and microfluidics. Microbots that are powered by self-phoretic mechanisms, such as Janus particles, often harness a solute fuel in their environment. Traditionally, self-phoretic particles are point like, but slender phoretic rods have become an increasingly prevalent design. While there has been substantial interest in creating efficient asymptotic theories for slender phoretic rods, hitherto such theories have been restricted to straight rods with axisymmetric patterning. However, modern manufacturing methods will soon allow fabrication of slender phoretic filaments with complex three-dimensional shapes. In this paper, we develop a slender body theory for the solute of self-diffusiophoretic filaments of arbitrary three-dimensional shape and patterning. We demonstrate analytically that, unlike other slender body theories, first-order azimuthal variations arising from curvature and confinement can make a leading-order contribution to the swimming kinematics.

Bibliographic note

Funding Information: T.D.M.-J. and P.K. gratefully acknowledge funding from EPSRC Bright Ideas grant no. EP/R041555/1. S.M. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement 714027 to S.M.). The authors would like to thank E. Lauga for helpful discussions on autophoretic theory, and L. Koens for helpful discussions on slender body theory. Publisher Copyright: © The Author(s), 2020. Published by Cambridge University Press. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.


Original languageEnglish
Article numberA24
Number of pages43
JournalJournal of Fluid Mechanics
Early online date9 Jul 2020
Publication statusPublished - 10 Sep 2020


  • slender-body theory, propulsion, Slender-body theory, Propulsion