On the retention mechanisms and secondary effects in microthermal field-flow fractionation of particles |
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Authors: | Josef Janča Jaroslav Stejskal |
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Institution: | 1. Tomas Bata University in Zlin, Department of Physics and Materials Engineering, Nad Stranemi 4511, 760 05 Zlin, Czech Republic;2. Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq.2, 162 06 Prague 6, Czech Republic |
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Abstract: | The behavior of nanometer or micrometer-sized particles, dispersed in liquid phase and exposed to temperature gradient, is a complex and not yet well understood phenomenon. Thermal field-flow fractionation (TFFF), using conventional-size channels, played an important role in the studies of this phenomenon. In addition to thermal diffusion (thermophoresis) and molecular diffusion or Brownian movement, several secondary effects such as particle–particle and/or particle–wall interactions, chemical equilibria with the components of the carrier liquid, buoyant and lift forces, etc., may contribute to the retention and complicate the understanding of the relations between the thermal diffusion and the characteristics of the retained particles. Microthermal FFF is a new high-performance technique allowing much easier manipulation and control of the operational parameters within an extended range of experimental conditions in comparison with conventional TFFF. Consequently, in combination with various other methods, it is well suited for a detailed investigation of the mentioned effects. In this work, some contradictory published results concerning the thermal diffusion of the colloidal particles, studied by TFFF but also by other methods, are analyzed and compared with our experimental findings. |
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Keywords: | Microthermal field-flow fractionation Particle separation Particle analysis Separation mechanisms |
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