Non stationary mass transfer in the flow due to a disk rotating in an Ostwald. fluid. Application to the measurement of the molecular diffusion coefficient in a polymer solution
✍ Scribed by C. Deslouis; B. Tribollet
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 888 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
We calculated the diffusion impedance to the surface of a rotating disk in an Ostwald fluid. The experimental study has been performed by a frequency analysis of the electrochemical impedance corresponding to the reduction of the potassium ferricyaaide in a KC1 (N) solution ofa high polymer additive (Polyox WSR 301). The fit of the experimental values with the theoretical expression allowed us to show that the molecular diffusion coefficient of the ferricyanide ion remains unchanged as regards to that in pure solvent, in solutions for which theapparent viscosity varies in a wide range. This result has heen explained by the smallness of the diffusing ion as compared to the correlation length of the entangled polymer.