Polymer and sphere diffusion in confinement

Abstract

We use video microscopy and particle tracking to study the diffusion of both colloidal spheres and polymers in slit microchannels. The molecules are allowed to sample the entire height of the microchannel. We find that the sphere data agrees well with a gap-averaged Oseen linear superposition approximation even at very high confinement whereas polymer chains at high confinement can not be modeled by this far field approach. We find that the polymer chain dynamics at high confinement can be explained well by a blob model scaling.