Thermophoresis of charged colloidal rods

Wang, Zilin; Kriegs, Hartmut; Dhont, Jan K. G.; Buitenhuis, Johan; Wiegand, Simone

doi:10.1039/c3sm51456k

Journal Article

FZJ-2013-04094

Thermophoresis of charged colloidal rods

Wang, Z. (Corresponding author)FZJ* ; Kriegs, H.FZJ* ; Buitenhuis, J.FZJ* ; Dhont, J. K. G.FZJ* ; Wiegand, S.FZJ*

2013
Royal Society of Chemistry (RSC) Cambridge

Soft matter 9(36), 8697 - 8704 (2013) [10.1039/c3sm51456k]

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Please use a persistent id in citations: http://hdl.handle.net/2128/22894 doi:10.1039/c3sm51456k

Abstract: The thermal diffusion behavior of dilute solutions of very long and thin, charged colloidal rods (fd-virus particles) is studied by a holographic grating technique. The Soret coefficient of the charged colloids is measured as a function of the Debye screening length, as well as the rod-concentration. The Soret coefficient of the fd-viruses increases monotonically with increasing Debye length, while there is a relatively weak dependence on the rod-concentration when the ionic strength is kept constant. An existing theory for thermal diffusion of charged spheres is extended to describe the thermal diffusion of long and thin charged rods, leading to an expression for the Soret coefficient in terms of the Debye length, the rod-core dimensions, and the surface charge density. The thermal diffusion coefficient of a charged colloidal rod is shown to be accurately represented, for arbitrary Debye lengths, by a superposition of spherical beads with the same diameter of the rod and the same surface charge density. The experimental Soret coefficients are compared with this and other theories, and are contrasted against the thermal diffusion behaviour of charged colloidal spheres.

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