Thickness effects in particle-tracking microrheology measurements of a fluid in a thin channel between gel and glass

Abstract

Particle-tracking microrheology was applied to a water layer less than a hundred micrometer thick sandwiched between gel and glass surfaces. The diffusion coefficient of the particles tended to decrease as the ratio of thickness to the particle radius decreased. The experimental results were in good agreement with the Faxén equation for particle mobility, which is derived by considering the hydrodynamic interaction between the particle and two solid surfaces.