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Dynamic Overlap Concentration Scale of Active Colloids

Mallory, Stewart A. and Omar, Ahmad K. and Brady, John F. (2020) Dynamic Overlap Concentration Scale of Active Colloids. . (Unpublished)

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By introducing the notion of a dynamic overlap concentration scale, we identify universal and previously unreported features of the mechanical properties of active colloids. These features are codified by recognizing that the characteristic length scale of an active particle's trajectory, the run-length, introduces a new concentration scale ϕ∗. Large-scale simulations of repulsive active Brownian particles (ABPs) confirm that this new run-length dependent concentration, which is the trajectory-space analogue of the overlap concentration in polymer solutions, delineates distinct concentration regimes in which interparticle collisions alter particle trajectories. Using ϕ∗ and concentration scales associated with colloidal jamming, the mechanical equation-of-state for ABPs can be collapsed onto a set of principal curves that contain a number of previously overlooked features. The inclusion of these features qualitatively alters previous predictions of the behavior for active colloids as we demonstrate by computing the spinodal for a suspension of purely-repulsive ABPs. Our findings suggest that dynamic overlap concentration scales should be of great utility in unraveling the behavior of active and driven systems.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Mallory, Stewart A.0000-0003-1364-7252
Omar, Ahmad K.0000-0002-6404-7612
Brady, John F.0000-0001-5817-9128
Additional Information:S.A.M. acknowledges financial support from the Arnold and Mabel Beckman Foundation. A.K.O. acknowledges support from the Schmidt Science Fellowship in partnership with the Rhodes Trust. J.F.B. acknowledges support by the National Science Foundation under Grant No. CBET-1803662. We gratefully acknowledge the support of the NVIDIA Corporation for the donation of the Titan V GPU used to carry out this work.
Funding AgencyGrant Number
Arnold and Mabel Beckman FoundationUNSPECIFIED
Schmidt Science FellowshipUNSPECIFIED
Record Number:CaltechAUTHORS:20201005-103534186
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105785
Deposited By: Tony Diaz
Deposited On:05 Oct 2020 17:53
Last Modified:05 Oct 2020 17:53

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