  Clay-polymer dispersions in aqueous solutions have attracted a great interest
in recent years due to their industrial applications and intriguing physical
properties. Aqueous solutions of bare Laponite particles are known to age
spontaneously from an ergodic state to a non ergodic state in a time varying
from hours to months depending on Laponite concentration. When a polymer
species like Polyethylene Oxide (PEO) is added to the solution, it weakly
adsorbs on clay particle surfaces modifying the effective interaction potential
between Laponite particles. A dynamic light scattering study, varying polymer
concentration at fixed polymer molecular weight (Mw=200.000 g/mol), has been
performed in order to understand the effect of polymer on the aging dynamics of
the system. The results obtained show that arresting phenomena between clay
particles are hindered if PEO is added and consequently the aging dynamics
slows down with increasing PEO concentration. This process is possibly due to
the progressive coverage of the clay surface by polymers that grow with
increasing PEO concentration and may lead to steric stabilization.
