Two-dimensional diffusion of colloids in polymer solutions
Journal
Molecular Physics
Journal Volume
103
Journal Issue
21-23 SPEC. ISS.
Pages
2897-2902
Date Issued
2005
Author(s)
Abstract
Enhanced digital videomicroscopy is used to study the two-dimensional diffusion of colloidal polystyrene spheres of diameter 0.99 μm in confined aqueous solutions of polymer PEO (polyethyleneoxide) of molecular weight 8 × 10 6. Diffusion is found to obey the Brownian motion law of linearity of the mean square displacement with time, with a constant appropriate to two dimensions. The diffusivity is determined for various polymer concentrations ranging from zero to those corresponding to dilute and semi-dilute polymer solutions. An abrupt slope change occurs near the polymer concentration of 0.002wt-%, which lies below the concentration at which the polymer chains begin to overlap.
Type
journal article