Soft Matter and Complex Systems Seminar

The Stokes law, which describes motion of particle in viscous liquid, and Einstein viscosity coefficient, which describes increase of viscosity when small amount of solid particles is added to viscous liquid, lie at the core of experiments probing hydrodynamic properties of immersed particles or liquid itself. We derive Stokes law and Einstein viscosity coefficient for complex liquids, in which viscosity is scale-dependent, i.e. it depends on wave vector in Fourier space. We also discover that the relation between calculated Stokes drag coefficient and Einstein coefficient is universal - it does not depend on the particular form of scale dependent viscosity, and is the same for all complex liquids.