Influence of mixing conditions on the rheological properties and structure of capillary suspensions
The rheological properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk liquid. These capillary suspensions exist either in the pendular state where the secondary fluid preferentially wets the particles or the capillary st...
| Publié dans: | Colloids and surfaces. A, Physicochemical and engineering aspects. - 1999. - 518(2017) vom: 05. Apr., Seite 85-97 |
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| Auteur principal: | |
| Autres auteurs: | , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2017
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| Accès à la collection: | Colloids and surfaces. A, Physicochemical and engineering aspects |
| Sujets: | Journal Article Agglomeration Capillary suspensions Droplet breakup Microstructure Rheology |
| Résumé: | The rheological properties of a suspension can be dramatically altered by adding a small amount of a secondary fluid that is immiscible with the bulk liquid. These capillary suspensions exist either in the pendular state where the secondary fluid preferentially wets the particles or the capillary state where the bulk fluid is preferentially wetting. The yield stress, as well as storage and loss moduli, depends on the size and distribution of secondary phase droplets created during sample preparation. Enhanced droplet breakup leads to stronger sample structures. In capillary state systems, this can be achieved by increasing the mixing speed and time of turbulent mixing using a dissolver stirrer. In the pendular state, increased mixing speed also leads to better droplet breakup, but spherical agglomeration is favored at longer times decreasing the yield stress. Additional mixing with a ball mill is shown to be beneficial to sample strength. The influence of viscosity variance between the bulk and second fluid on the droplet breakup is excluded by performing experiments with viscosity-matched fluids. These experiments show that the capillary state competes with the formation of Pickering emulsion droplets and is often more difficult to achieve than the pendular state |
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| Description: | Date Revised 24.03.2024 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 0927-7757 |
| DOI: | 10.1016/j.colsurfa.2017.01.026 |