Title: Anisotropic thermophoresis,
Abstract: Colloidal migration in temperature gradient is referred to as thermophoresis.
In contrast to particles with spherical shape, we show that elongated colloids
may have a thermophoretic response that varies with the colloid orientation.
Remarkably, this can translate into a non-vanishing thermophoretic force in the
direction perpendicular to the temperature gradient. Oppositely to the friction
force, the thermophoretic force of a rod oriented with the temperature gradient
can be larger or smaller than when oriented perpendicular to it. The precise
anisotropic thermophoretic behavior clearly depends on the colloidal rod aspect
ratio, and also on its surface details, which provides an interesting
tunability to the devices constructed based on this principle. By means of
mesoscale hydrodynamic simulations, we characterize this effect for different
types of rod-like colloids.