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Tunable shear thickening in suspensions.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Lin, Neil YC 
Cates, Michael E 
Sun, Jin 
Cohen, Itai 

Abstract

Shear thickening, an increase of viscosity with shear rate, is a ubiquitous phenomenon in suspended materials that has implications for broad technological applications. Controlling this thickening behavior remains a major challenge and has led to empirical strategies ranging from altering the particle surfaces and shape to modifying the solvent properties. However, none of these methods allows for tuning of flow properties during shear itself. Here, we demonstrate that by strategic imposition of a high-frequency and low-amplitude shear perturbation orthogonal to the primary shearing flow, we can largely eradicate shear thickening. The orthogonal shear effectively becomes a regulator for controlling thickening in the suspension, allowing the viscosity to be reduced by up to 2 decades on demand. In a separate setup, we show that such effects can be induced by simply agitating the sample transversely to the primary shear direction. Overall, the ability of in situ manipulation of shear thickening paves a route toward creating materials whose mechanical properties can be controlled.

Description

Keywords

colloidal suspensions, flow control, rheology, shear thickening

Journal Title

Proc Natl Acad Sci U S A

Conference Name

Journal ISSN

0027-8424
1091-6490

Volume Title

Publisher

Proceedings of the National Academy of Sciences
Sponsorship
Engineering and Physical Sciences Research Council (EP/J007404/1)
I.C. and N.Y.C.L. gratefully acknowledge the Weitz Laboratory at Harvard University, School of Engineering and Applied Sciences for generous use of their rheometry facility. I.C. and N.Y.C.L. were supported by National Science Foundation (NSF) CBET-PMP Award 1232666 and continued support from NSF CBET-PMP Award 1509308. C.N. and J.S. acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC), EP/N025318/1. M.E.C. is supported by the Royal Society and EPSRC Grant EP/J007404. This work also made use of the Cornell Center for Materials Research Shared Facilities, which are supported through the NSF Materials Research Science and Engineering Centers Program (DMR-1120296).
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