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Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids

[Image: see text] The mechanical properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk phase. The substantial changes in the strength of these capillary suspensions arise due to the capillary force inducing a percolating...

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Autores principales: Bossler, Frank, Koos, Erin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2016
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4757740/
https://www.ncbi.nlm.nih.gov/pubmed/26807651
http://dx.doi.org/10.1021/acs.langmuir.5b04246
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author Bossler, Frank
Koos, Erin
author_facet Bossler, Frank
Koos, Erin
author_sort Bossler, Frank
collection PubMed
description [Image: see text] The mechanical properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk phase. The substantial changes in the strength of these capillary suspensions arise due to the capillary force inducing a percolating particle network. Spatial information on the structure of the particle networks is obtained using confocal microscopy. It is possible, for the first time, to visualize the different types of percolating structures of capillary suspensions in situ. These capillary networks are unique from other types of particulate networks due to the nature of the capillary attraction. We investigate the influence of the three-phase contact angle on the structure of an oil-based capillary suspension with silica microspheres. Contact angles smaller than 90° lead to pendular networks of particles connected with single capillary bridges or clusters comparable to the funicular state in wet granular matter, whereas a different clustered structure, the capillary state, forms for angles larger than 90°. Particle pair distribution functions are obtained by image analysis, which demonstrate differences in the network microstructures. When porous particles are used, the pendular conformation also appears for apparent contact angles larger than 90°. The complex shear modulus can be correlated to these microstructural changes. When the percolating structure is formed, the complex shear modulus increases by nearly three decades. Pendular bridges lead to stronger networks than the capillary state network conformations, but the capillary state clusters are nevertheless much stronger than pure suspensions without the added liquid.
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spelling pubmed-47577402016-03-03 Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids Bossler, Frank Koos, Erin Langmuir [Image: see text] The mechanical properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk phase. The substantial changes in the strength of these capillary suspensions arise due to the capillary force inducing a percolating particle network. Spatial information on the structure of the particle networks is obtained using confocal microscopy. It is possible, for the first time, to visualize the different types of percolating structures of capillary suspensions in situ. These capillary networks are unique from other types of particulate networks due to the nature of the capillary attraction. We investigate the influence of the three-phase contact angle on the structure of an oil-based capillary suspension with silica microspheres. Contact angles smaller than 90° lead to pendular networks of particles connected with single capillary bridges or clusters comparable to the funicular state in wet granular matter, whereas a different clustered structure, the capillary state, forms for angles larger than 90°. Particle pair distribution functions are obtained by image analysis, which demonstrate differences in the network microstructures. When porous particles are used, the pendular conformation also appears for apparent contact angles larger than 90°. The complex shear modulus can be correlated to these microstructural changes. When the percolating structure is formed, the complex shear modulus increases by nearly three decades. Pendular bridges lead to stronger networks than the capillary state network conformations, but the capillary state clusters are nevertheless much stronger than pure suspensions without the added liquid. American Chemical Society 2016-01-25 2016-02-16 /pmc/articles/PMC4757740/ /pubmed/26807651 http://dx.doi.org/10.1021/acs.langmuir.5b04246 Text en Copyright © 2016 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Bossler, Frank
Koos, Erin
Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title_full Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title_fullStr Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title_full_unstemmed Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title_short Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
title_sort structure of particle networks in capillary suspensions with wetting and nonwetting fluids
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4757740/
https://www.ncbi.nlm.nih.gov/pubmed/26807651
http://dx.doi.org/10.1021/acs.langmuir.5b04246
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