Structure of Particle Networks in Capillary Suspensions with Wetting and Nonwetting Fluids
| Autor: | Erin Koos, Frank Bossler |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Capillary pressure
Materials science Capillary bridges Capillary action Analytical chemistry 02 engineering and technology Surfaces and Interfaces 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Capillary number Article 0104 chemical sciences Suspension (chemistry) Contact angle Physics::Fluid Dynamics Condensed Matter::Soft Condensed Matter Chemical engineering Electrochemistry Particle General Materials Science Wetting 0210 nano-technology Spectroscopy |
| Zdroj: | Langmuir |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | 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. ispartof: Langmuir vol:32 issue:6 pages:1489-1501 ispartof: location:United States status: published |
| Databáze: | OpenAIRE |
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