Diffusion of charged nano-disks in aqueous media: Influence of competing inter-particle interactions and thermal effects
| Autor: | Krishnamurthy Muralidhar, Yogesh M. Joshi, Yogesh M. Nimdeo |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Work (thermodynamics)
Chemistry Applied Mathematics General Chemical Engineering Diffusion Mass diffusivity Thermodynamics Nanoparticle 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Thermal diffusivity 01 natural sciences Industrial and Manufacturing Engineering 0104 chemical sciences Condensed Matter::Soft Condensed Matter Colloid Ultrapure water Particle 0210 nano-technology |
| Zdroj: | Chemical Engineering Science. 164:71-80 |
| ISSN: | 0009-2509 |
| Popis: | In this work we investigate binary mass diffusion of negatively charged disk-shaped nanoparticles of Laponite JS in ultrapure water using Mach-Zehnder interferometry aided by a sensitivity analysis. We observe that binary mass diffusivity of aqueous suspension shows a consistent enhancement with concentration of Laponite at a given temperature. The dependence on temperature, however, is observed to be non-monotonic, wherein the binary mass diffusivity first increases with temperature up to 20 °C while decreasing at higher temperatures. We propose that the observed non-monotonic dependence of binary diffusivity on temperature is due to competing effects such as: thermal energy of Laponite particles, that of counterions, and the magnitude of charge on the Laponite particles. These factors affect the aggregation rate of Laponite particles leading to the behaviour observed in the experiments. Interestingly the binary diffusivity of Laponite obtained in the present work is significantly higher than the self-diffusion coefficient of a corresponding hard disk. We propose that enhanced binary diffusivity is due to repulsive interaction among the Laponite particles that augments mobility of the solute in ultrapure water. |
| Databáze: | OpenAIRE |
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