| Journal: | Revista mexicana de física E |
| Database: | PERIÓDICA |
| System number: | 000431231 |
| ISSN: | 1870-3542 |
| Authors: | Hamilton, G1 Disharoon, Z1 Sanabria, H1 |
| Institutions: | 1Clemson University, Clemson, South Carolina. Estados Unidos de América |
| Year: | 2018 |
| Season: | Jul-Dic |
| Volumen: | 64 |
| Number: | 2 |
| Country: | México |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Analítico, teórico |
| English abstract | The response of a fluid to deformation by shear stress is known as shear viscosity. This concept arises from a macroscopic view and was first introduced by Sir Isaac Newton. Nonetheless, a fluid is a series of moving molecules that are constrained by the shape of the container. Such a view begs the treatment of viscosity from a microscopic or molecular view, a task undertaken by both Einstein and Smoluchowski independently. Here we revisit the concept of viscosity and experimentally verify that the viscosity at a molecular level, which describes the drag force, is the same as the macroscopic shear viscosity; hence, bridging different length- and time-scales. For capturing the shear stress response of a fluid, we use classical rheometry; at a molecular level we use probe diffusion to determine the local viscosity from the translational and rotational motions. In these cases, we use Fluorescence Correlation Spectroscopy and Time Resolved Fluorescence, respectively. By increasing the osmolyte (Glucose-D) concentration, we change the viscosity and find that these methods provide a unified view of viscosity, bridging the gap between the macroscopic and nanoscale regimes. Moreover, Glucose’s viscosity follows a scaling factor more commonly associated to solutions of branched polymer because the probe dimensions are comparable to the dimensions of the osmolyte that exerts the drag |
| Disciplines: | Física y astronomía |
| Keyword: | Mecánica, elasticidad y reología, Espectroscopía de correlación de fluorescencia, Reometría, Macroviscosidad |
| Keyword: | Anisotropía de fluorescencia, Difusión de la sonda, Fluorescence correlation spectroscopy, Rheometry, Fluorescence anisotropy, Probe diffusion, Macroviscosity |
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