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Mixed active-passive systems in confinement
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Williams, Stephen (2022) Mixed active-passive systems in confinement. PhD thesis, University of Warwick.
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WRAP_Theses_Williams_2022.pdf - Submitted Version - Requires a PDF viewer. Download (8Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b3858172
Abstract
The dynamics of passive colloidal particles are explored when they interact with active Chlamydomonas reinhardtii, a green micro-algae. Through the implementation of different confining microfluidic geometries, we examine the resulting colloidal distributions and characterise the interactions which lead to them. Experiments are outlined in which we characterise the positional dependence of the `jumps' passive particles undergo, which result from interacting with the active particles. These jumps are then used to reconstruct the overall positional distributions. Additionally, we outline experiments performed in a circular microfluidic confinement. By exploiting the aforementioned positional distribution of colloids and a semi-permeable membrane, this microfluidic device can be used to segregate the passive particles out of the mixture. Finally, features of a model are outlined which allows for the modelling of active-passive mixtures. The active particle of which is easily tuneable, allowing both pusher or puller type swimmers, as well as a variety of boundary scattering behaviours. Results show that confinement results in inhomogeneous swimmer dynamics, which then feed into the behaviour of passive particle dynamics. Microswimmer confinement is a clear example in which spatial inhomogeneities lead to passive particle accumulation and, upon implementing a semi-permeable membrane, can be used to perform particle demixing. Such interactions present exciting new possibilities for controlling micro-scale particles using active particles whose dynamics have such spatially dependent characteristics.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QC Physics Q Science > QD Chemistry |
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Library of Congress Subject Headings (LCSH): | Chlamydomonas reinhardtii, Colloids, Microfluidics, Biophysics, Microelectromechanical systems | ||||
Official Date: | April 2022 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Department of Physics | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Polin, Marco | ||||
Format of File: | |||||
Extent: | ix, 110 pages : illustrations | ||||
Language: | eng |
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