Microrheology close to an equilibrium phase transition

: Reinhardt, J.; Scacchi, A.; Brader, J. M.

Publisher: AMER INST PHYSICS

: MELVILLE

: 2014

: Journal of Chemical Physics

: JOURNAL OF CHEMICAL PHYSICS

: J CHEM PHYS

: 144901

: 140

: 14

: 10

: 0021-9606

: 1089-7690

DOI: https://doi.org/10.1063/1.4870497

We investigate the microstructural and microrheological response to a tracer particle of a two-dimensional colloidal suspension under thermodynamic conditions close to a liquid-gas phase boundary. On the liquid side of the binodal, increasing the velocity of the (repulsive) tracer leads to the development of a pronounced cavitation bubble, within which the concentration of colloidal particles is strongly depleted. The tendency of the liquid to cavitate is characterized by a dimensionless "colloidal cavitation" number. On the gas side of the binodal, a pulled (attractive) tracer leaves behind it an extended trail of colloidal liquid, arising from downstream advection of a wetting layer on its surface. For both situations the velocity dependent friction is calculated. (C) 2014 AIP Publishing LLC.