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Deswelling and deformation of microgels in concentrated packings

Bouhid de Aguiar, Izabella and Van de Laar, Ties and Meireles, Martine and Bouchoux, Antoine and Sprakel, Joris and Schroën, Karin Deswelling and deformation of microgels in concentrated packings. (2017) Scientific Reports, 7 (1). 1-11. ISSN 2045-2322

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Official URL: https://doi.org/10.1038/s41598-017-10788-y

Abstract

Increasing the particle density of a suspension of microgel colloids above the point of random-close packing, must involve deformations of the particle to accommodate the increase in volume fraction. By contrast to the isotropic osmotic deswelling of soft particles, the particle-particle contacts give rise to a non-homogeneous pressure, raising the question if these deformations occur through homogeneous deswelling or by the formation of facets. Here we aim to answer this question through a combination of imaging of individual microgels in dense packings and a simple model to describe the balance between shape versus volume changes. We find a transition from shape changes at low pressures to volume changes at high pressures, which can be explained qualitatively with our model. Whereas contact mechanics govern at low pressures giving rise to facets, osmotic effects govern at higher pressures, which leads to a more homogeneous deswelling. Our results show that both types of deformation play a large role in highly concentrated microgel suspensions and thus must be taken into account to arrive at an accurate description of the structure, dynamics and mechanics of concentrated suspensions of soft spheres.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
Université de Toulouse > Institut National des Sciences Appliquées de Toulouse - INSA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Wageningen University & Research - WUR (NETHERLANDS)
Laboratory name:
Funders:
European Commission–Education, Audiovisual and Culture Executive Agency (EACEA)
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Deposited By: Loetitia MOYA
Deposited On:15 Oct 2018 06:52

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