Self-Propulsion of Janus Particles near a Brush-Functionalized Substrate

Thermophoresis is a common mechanism that can drive autonomous motion of Janus particles under the right environment. Despite recent efforts to investigate the mechanism underlying the self-propulsion of thermophoretic particles, the interaction of particles with the substrate underneath the particl...

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Bibliographic Details
Published in:Langmuir 2020-07, Vol.36 (27), p.7775-7780
Main Authors: Heidari, Mojdeh, Bregulla, Andreas, Landin, Santiago Muinos, Cichos, Frank, von Klitzing, Regine
Format: Article
Language:English
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Summary:Thermophoresis is a common mechanism that can drive autonomous motion of Janus particles under the right environment. Despite recent efforts to investigate the mechanism underlying the self-propulsion of thermophoretic particles, the interaction of particles with the substrate underneath the particle has remained unclear. In this work, we explore the impact of poly­(N-isopropylacrylamide) (PNIPAM)-functionalized substrate with various chain lengths on the active motion of a single polystyrene particle half-coated with gold (Au–PS). We show how the modification of the substrate with polymer brushes enhances the particle velocity, where brush chain length plays a significant role as well. The results demonstrate the intrinsic dependence of particle velocity on the flow boundary condition and the thermo-osmotic slip at the interface.
ISSN:0743-7463
1520-5827
DOI:10.1021/acs.langmuir.0c00461