Dynamic light scattering and viscoelasticity from nafion in alcohols aqueous solution
| Autor: | 李淑珍 |
|---|---|
| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 In this research work, Physical properties of Nafion solution were studied. Dynamic light scattering (DLS), membrane osmometer, and rheometer were used to study the solution properties of Nafion in mixtures of alcohols/water solvents. Dynamic light scattering data of Nafion/methanol/water solution revealed that, at a concentration below 3 mg/ml, it has one relaxation mode, but at concentrations above 5 mg/ml, two relaxation modes were observed with slow mode shifted to longer time relaxation while Nafion concentration was increased, Membrane osmometer data showed that π/C decreased with increasing Nafion concentration, while Nafion concentration was between 0.8 mg/ml and 1 mg/ml, indicating the aggregation of Nafion molecules. The rheometic experiment also showed the aggregation behavior in Nafion solution.The aggregation behavior of Nafion/alcohols/water solution is attributed two types of clusters: one is primary hydrophobic cluster, the other is ionic secondary cluster. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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