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Updated: Mar 20, 2026

Reactive Inkjet Printing and Propulsion Analysis of Silk-based Self-propelled Micro-stirrers
Published on: April 26, 2019
The efficiency of self-phoretic propulsion mechanisms with surface reaction heterogeneity
Patrick Kreissl1, Christian Holm1, Joost de Graaf1
1Institute for Computational Physics (ICP), University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
Abstract:
We consider the efficiency of self-phoretic colloidal particles (swimmers) as a function of the heterogeneity in the surface reaction rate. The set of fluid, species, and electrostatic continuity equations is solved analytically using a linearization and numerically using a finite-element method. To compare spherical swimmers of different size and with heterogeneous catalytic conversion rates, a "swimmer efficiency" functional η is introduced. It is proven that in order to obtain maximum swimmer efficiency, the reactivity has to be localized at the pole(s). Our results also shed light on the sensitivity of the propulsion speed to details of the surface reactivity, a property that is notoriously hard to measure. This insight can be utilized in the design of new self-phoretic swimmers.
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