Chemical and physical properties of colloids in aqueous dispersions are dominated by their surface properties caused by the large surface to mass ratio. Investigation of interactions at the particle-solvent interface provides information about the particle surface. In addition, slight variations of the particle-solvent interface generate substantial alteration of thermophoresis, which itself is still a not completely understood phenomenon. This phenomenon is studied in thermal field-flow fractionation (ThFFF), a quasi-chromatographic technique to fractionate colloids with respect to their thermophoretic mobility.We present the influence of zeta potential and type of electrolyte on retention behavior in ThFFF. A relation to theoretical models of thermophoresis is revealed by observation of thermoelectric effects. The capability of ThFFF to separate particles with equal hydrodynamic size, as determined by dynamic light scattering (DLS) and asymmetrical flow field-flow fractionation (AF-FFF), is demonstrated. In addition, we discuss the potential to determine particle surface properties by thermophoretical investigations.

New insight into colloid-solvent interactions analyzed by thermal field-flow fractionation

244th National Meeting (2012)

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