Singh, Dhruv, Uspal, William, Popescu, Mihail et al. (2 more authors) (2018) Photogravitactic Microswimmers. ADVANCED FUNCTIONAL MATERIALS. 1706660. ISSN 1616-301X
Abstract
Phototactic microorganisms are commonly observed to respond to natural sunlight by swimming upward against gravity. This study demonstrates that synthetic photochemically active microswimmers can also swim against gravity. The particles initially sediment and, when illuminated at low light intensities exhibit wall-bound states of motion near the bottom surface. Upon increasing the intensity of light, the artificial swimmers lift off from the wall and swim against gravity and away from the light source. This motion in the bulk has been further confirmed using holographic microscopy. A theoretical model is presented within the framework of self-diffusiophoresis, which allows to unequivocally identify the photochemical activity and the phototactic response as key mechanisms in the observed phenomenology. Since the lift-off threshold intensity depends on the particle size, it can be exploited to selectively address particles with the same density from a polydisperse mixture of active particles and move them in or out of the boundary region. This study provides a simple design strategy to fabricate artificial microswimmers whose two- or three-dimensional swimming behavior can be controlled with light.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Keywords: | Janus particles,artificial microswimmers,light-driven micromotors,phototaxis,self-propulsion |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 09 Mar 2018 09:10 |
Last Modified: | 13 Mar 2025 05:24 |
Published Version: | https://doi.org/10.1002/adfm.201706660 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1002/adfm.201706660 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:128394 |