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Thermophoresis as a Means for Manipulations with Macromolecules and Particles
Eighth International Meeting on Thermodiffusion (2008)
  • Semen N. Semenov
  • Martin Schimpf, Boise State University
Thermophoretic focusing and moving of isolated macromolecules and particles is theoretically examined. As the physical base for the focusing, the temperature and concentration dependence of the thermodiffusion coefficient in the unary solvent in binary solvent system are considered. Focusing may be occurred when the thermodiffusion coefficient positive (corresponding to the movement to old wall) at higher temperatures becomes zero and then negative in the temperature decrease. In the opposite case, the defocusing, that is the establishment of a zone free of the considered polymer or particles may occur. In the consideration of the thermophoresis, the mass transport equations and the solvent and solute dynamic parameters obtained previously are used. As shown, in unary solvent the focusing may be obtained for the solutes having very low interaction with the solvent, where the interaction of solvophilic and solvophobic groups are almost cancelled one another. This effect may have a place for polymer surfactants and particles with respective properties. The use of binary solvent systems may allow for a wider selection of solutes for manipulations. In such systems, the focused solute should have thermophoretic properties intermediate between the properties of the solvent components. Different kinds of polymers and particles having different thermophoretic properties could be focused at different regions. To have the possibility to work with a wider range of solutes, the mixture of limitedly miscible solvents can be used. Here, the limits of the difference between thermophoretic properties, where the solutes should be ranged, are much wider. In such systems, when temperature is below some critical point, the solvent layering can occur. Near the boundary between the solvent layers, the solutes in the wide range of properties may be focused. The focused zones of suspended particles or polymers or the zones free of these solutes can be moved by the scanning of the temperature profile in the system, what makes thermophoretic focusing a promising means for the manipulations with prepared layers of particles and macromolecules.
Publication Date
June, 2008
Citation Information
Semen N. Semenov and Martin Schimpf. "Thermophoresis as a Means for Manipulations with Macromolecules and Particles" Eighth International Meeting on Thermodiffusion (2008)
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