Hydrodynamic boundary effects on thermophoresis of confined colloids
Language
en
Article de revue
This item was published in
Physical Review Letters. 2016, vol. 116, p. 138302
American Physical Society
English Abstract
We study hydrodynamic slowing-down of a particle moving in a temperature gradient perpendicular to a wall. At distances much smaller than the particle radius, h << a, lubrication approximation leads to the reduced velocity ...Read more >
We study hydrodynamic slowing-down of a particle moving in a temperature gradient perpendicular to a wall. At distances much smaller than the particle radius, h << a, lubrication approximation leads to the reduced velocity u/u0 = 3 h/a (ln(a/h) − 9/4), where u0 is the velocity in the bulk. With Brenner's result for confined diffusion, we find that the trapping efficiency, or effective Soret coefficient , increases logarithmically as the particle gets very close to the wall. Our results provide a quantitative explanation for the recently observed enhancement of thermophoretic trapping at short distances. Our discussion of parallel and perpendicular thermophoresis in a capillary, reveals a good agreement with experiments on charged polystyrene particles, and sheds some light on a controversy concerning the size-dependence and the non-equilibrium nature of the Soret effect.Read less <
Origin
Hal imported