Tuning the motility and directionality of self-propelled colloids

Abstract

Microorganisms are able to overcome the thermal randomness of their surroundings by harvesting energy to navigate in viscous fluid environments. In a similar manner, synthetic colloidal microswimmers are capable of mimicking complex biolocomotion by means of simple self-propulsion mechanisms. Although experimentally the speed of active particles can be controlled by e.g. self-generated chemical and thermal gradients, an in-situ change of swimming direction remains a challenge. In this work, we study self-propulsion of half-coated spherical colloids in critical binary mixtures and show that the coupling of local body forces, induced by laser illumination, and the wetting properties of the colloid, can be used to finely tune both the colloid's swimming speed and its directionality. We experimentally and numerically demonstrate that the direction of motion can be reversibly switched by means of the size and shape of the droplet(s) nucleated around the colloid, depending on the particle radius and the fluid's ambient temperature. Moreover, the aforementioned features enable the possibility to realize both negative and positive phototaxis in light intensity gradients. Our results can be extended to other types of half-coated microswimmers, provided that both of their hemispheres are selectively made active but with distinct physical properties.

arXiv comment12 pages, 5 figures. Scientific Reports (Received: 04 August 2017, accepted: 04 October 2017, published online: 02 November 2017)

References in corpus (23)

• Active Particles in Complex and Crowded Environments
• Self-motile colloidal particles: from directed propulsion to random walk
• Physics of Microswimmers - Single Particle Motion and Collective Behavior
• Active Brownian Particles. From Individual to Collective Stochastic Dynamics
• Active Motion of Janus Particle by Self-thermophoresis in Defocused Laser Beam
• Designing phoretic micro- and nano-swimmers
• Sedimentation of active colloidal suspensions
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Phototaxis of synthetic microswimmers in optical landscapes
• Clusters, asters and collective oscillations in chemotactic colloids
• Dynamics of self-propelled Janus particles in viscoelastic fluids
• Phoretic Motion of Spheroidal Particles Due To Self-Generated Solute Gradients
• Flow pattern in the vicinity of self-propelling hot Janus particles
• Interface and contact line motion in a two phase fluid under shear flow
• A steering mechanism for phototaxis in Chlamydomonas
• Rippling patterns in aggregates of myxobacteria arise from cell-cell collisions
• Transient dynamics of a colloidal particle driven through a viscoelastic fluid
• Geometric tuning of self-propulsion for Janus catalytic particles
• Self-diffusiophoresis of Janus particles in near-critical mixtures
• Self-propulsion mechanism of active Janus particles in near-critical binary mixtures
• Hot Microswimmers
• Diffusion properties of active particles with directional reversal
• Efficacy of self-phoretic colloids and microswimmers

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