Volume 9, Issue 8 e202300225
Research Article

Spatial Patterning of Micromotor Aggregation and Flux

Dr. David P. Rivas

Dr. David P. Rivas

Department of Mechanical Engineering, University of Delaware, 130 Academy Street, Newark, DE 19716

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Max Sokolich

Max Sokolich

Department of Mechanical Engineering, University of Delaware, 130 Academy Street, Newark, DE 19716

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Prof. Dr. Sambeeta Das

Corresponding Author

Prof. Dr. Sambeeta Das

Department of Mechanical Engineering, University of Delaware, 130 Academy Street, Newark, DE 19716

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First published: 20 June 2023

Abstract

Using a spatially varying light pattern with light activated semi-conductor based magnetic micromotors, we study the difference in micromotor flux between illuminated and non-illuminated regions in the presence and absence of an applied magnetic field. We find that the magnetic field enhances the flux of the motors which we attribute to a straightening of the micromotor trajectories which decreases the time they spend in the illuminated region. We also demonstrate spatially patterned light-induced aggregation of the micromotors and study its time evolution at various micromotor concentrations. Although light induced aggregation has been observed previously, spatial patterning of aggregation demonstrates a further means of control which could be relevant to swarm control or self-assembly applications. Overall, these results draw attention to the effect of trajectory shape on the flux of active colloids as well as the concentration dependence of aggregation and its time dependence within a spatially patterned region, which is not only pertinent to self-assembly and swarm control, but also provides insight into the behavior of active matter systems with spatially varying activity levels.

Conflict of interest

The authors have no conflict of interest to declare.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.