Constraint Dependence of Active Depletion Forces on Passive Particles

Peng Liu, Simin Ye, Fangfu Ye, Ke Chen, and Mingcheng Yang

Phys. Rev. Lett. 124, 158001 – Published 13 April 2020

Abstract

Using simulations and experiments, we demonstrate that the effective interaction between passive particles in an active bath substantially depends on an external constraint suffered by the passive particles. Particularly, the effective interaction between two free passive particles, which is directly measured in simulation, is qualitatively different from the one between two fixed particles. Moreover, we find that the friction experienced by the passive particles—a kinematic constraint—similarly influences the effective interaction. These remarkable features are in significant contrast to the equilibrium cases, and mainly arise from the accumulation of the active particles near the concave gap formed by the passive spheres. This constraint dependence not only deepens our understanding of the “active depletion force,” but also provides an additional tool to tune the effective interactions in an active bath.

Received 6 September 2019
Revised 22 February 2020
Accepted 25 March 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.158001

Physics Subject Headings (PhySH)

Depletion interactions

Colloids Living matter & active matter

Optical tweezers

Polymers & Soft Matter

Authors & Affiliations

Peng Liu^1,2,*, Simin Ye^1,2,*, Fangfu Ye^1,2,3,4,†, Ke Chen^1,2,4,‡, and Mingcheng Yang^1,2,§

¹Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
²School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
³Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325001, China
⁴Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China

^*These authors contributed equally to this work.
^†fye@iphy.ac.cn
^‡kechen@iphy.ac.cn
^§mcyang@iphy.ac.cn

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 124, Iss. 15 — 17 April 2020

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review Letters