Shear-Induced Diffusion of Platelike Particles in Microchannels

We exploit the recent developments of microfluidic technologies to investigate the collective shear-induced diffusion in suspensions of micron-sized particles. Whereas spherical particles do not diffuse on the time scale of our experiments, the results with platelike clay particles show a strong cross-stream shear-induced diffusivity at low volume fraction (phi(0)<= 0.01). Moreover, we find a linear dependence of the collective diffusion coefficient with the average shear rate (in the range 10(2)-10(4) s(-1)) and the particle concentration. These data are in good agreement with previous experimental and theoretical results for spheres when rescaled with the particle number density.