Issue 12, 2013
From the journal:

Soft Matter

Slip of gels in colloid–polymer mixtures under shear†

Pierre Ballesta,*a   Nick Koumakis,a   Rut Besseling,c   Wilson C. K. Poonb  and  George Petekidis*a  

* Corresponding authors

a IESL-FORTH and Department of Materials Science and Technology, University of Crete, Heraklion, Crete, Greece
E-mail: bpballest@aol.com, georgp@iesl.forth.gr

b SUPA and School of Physics, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh, UK

c Merck Sharp and Dohme, Molenstraat 110, Oss, Netherland

Abstract

We investigate the time-dependent rheology and slip behaviour of colloidal gels formed under polymer-induced depletion attraction. The shape of the flow curves at low applied shear rates is suggestive of slip, which we confirm using confocal imaging. Time-dependent linear viscoelastic measurements show an unexpected drop of the elastic modulus below the viscous one after a critical time. We present a dynamic phase diagram characterizing the dependence of slip on polymer concentration and colloid volume fraction. Confocal imaging links slip to the restructuring of clusters with time, which leads to a reduction of the number of contacts between the colloidal network and the rheometer surfaces. Such behaviour is shear rate dependent and correlated to changes in the gel structure, which changed from independent small aggregates at high shear rates to percolated clusters at low shear rates.

Graphical abstract: Slip of gels in colloid–polymer mixtures under shear

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Article information

DOI
https://doi.org/10.1039/C3SM27626K
Article type
Paper
Submitted
14 Nov 2012
Accepted
15 Jan 2013
First published
07 Feb 2013

Soft Matter, 2013,9, 3237-3245

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Slip of gels in colloid–polymer mixtures under shear

P. Ballesta, N. Koumakis, R. Besseling, W. C. K. Poon and G. Petekidis, Soft Matter, 2013, 9, 3237 DOI: 10.1039/C3SM27626K

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