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Universal reshaping of arrested colloidal gels via active doping

Mallory, S. A. and Bowers, M. L. and Cacciuto, A. (2020) Universal reshaping of arrested colloidal gels via active doping. Journal of Chemical Physics, 153 (8). Art. No. 084901. ISSN 0021-9606.

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Colloids that interact via a short-range attraction serve as the primary building blocks for a broad range of self-assembled materials. However, one of the well-known drawbacks to this strategy is that these building blocks rapidly and readily condense into a metastable colloidal gel. Using computer simulations, we illustrate how the addition of a small fraction of purely repulsive self-propelled colloids, a technique referred to as active doping, can prevent the formation of this metastable gel state and drive the system toward its thermodynamically favored crystalline target structure. The simplicity and robust nature of this strategy offers a systematic and generic pathway to improving the self-assembly of a large number of complex colloidal structures. We discuss in detail the process by which this feat is accomplished and provide quantitative metrics for exploiting it to modulate the self-assembly. We provide evidence for the generic nature of this approach by demonstrating that it remains robust under a number of different anisotropic short-ranged pair interactions in both two and three dimensions. In addition, we report on a novel microphase in mixtures of passive and active colloids. For a broad range of self-propelling velocities, it is possible to stabilize a suspension of fairly monodisperse finite-size crystallites. Surprisingly, this microphase is also insensitive to the underlying pair interaction between building blocks. The active stabilization of these moderately sized monodisperse clusters is quite remarkable and should be of great utility in the design of hierarchical self-assembly strategies. This work further bolsters the notion that active forces can play a pivotal role in directing colloidal self-assembly.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Mallory, S. A.0000-0003-1364-7252
Bowers, M. L.0000-0001-8450-7033
Cacciuto, A.0000-0003-1774-6311
Additional Information:© 2020 Published under license by AIP Publishing. Submitted: 4 June 2020; Accepted: 5 August 2020; Published Online: 24 August 2020. A.C. acknowledges financial support from the National Science Foundation under Grant No. DMR-1703873. S.A.M. acknowledges financial support from the Arnold and Mabel Beckman Foundation. The authors gratefully acknowledge the support of the NVIDIA Corporation for the donation of the Titan V GPU used to carry out this work. M.L.B. acknowledges support from Columbia University through the Guthikonda Fellowship. The authors thank Austin Dulaney, Ahmad Omar, and Hyeongjoo Row for insightful discussions and a critical reading of an early version of the manuscript. The authors declare no competing financial interest.
Funding AgencyGrant Number
Arnold and Mabel Beckman FoundationUNSPECIFIED
Columbia UniversityUNSPECIFIED
Issue or Number:8
Record Number:CaltechAUTHORS:20200713-092738589
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Official Citation:Universal reshaping of arrested colloidal gels via active doping. S. A. Mallory, M. L. Bowers, and A. Cacciuto. The Journal of Chemical Physics 153:8; doi: 10.1063/5.0016514
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104348
Deposited By: Tony Diaz
Deposited On:13 Jul 2020 19:06
Last Modified:24 Aug 2020 20:31

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