Interfacial colloidal monolayers under steady shear: structure and flow profiles
| Autor: | Buttinoni, Ivo, Zell, Zachary A., Squires, Todd M., Isa, Lucio |
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| Rok vydání: | 2015 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1039/c5sm01693b |
| Popis: | We study the coupling between the structural dynamics and rheological response of charged colloidal monolayers at water/oil interfaces, driven into steady shear by a microdisk rotating at a controlled angular velocity. The flow causes particles to layer into rotating concentric rings linked to the local, position-dependent shear rate, which triggers two distinct dynamical regimes: particles move continuously "Flowing") close to the microdisk, or exhibit intermittent "Hopping" between local energy minima farther away. The shear-rate dependent surface viscosity of a monolayer can be extracted from an interfacial stress balance, giving "macroscopic" flow curves whose behavior corresponds to the distinct microscopic regimes of particle motion. Hopping Regions correspond to a surface yield stress $\eta \sim \tau_S^Y \dot{\gamma}^{-1}$, whereas Flowing Regions exhibit surface viscosities with power-law shear-thinning characteristics. Comment: Supplementary Materials also present. Soft Matter, 2015 |
| Databáze: | arXiv |
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