SLIDING OF A POLYMER DROPLET ON GLASS OBSERVED BY EPR

A preliminary investigation of the sliding of droplets of aqueous solu tions of poly(ethylene oxide) and of the melt of polydimethylsiloxane in the presence of nonwetting defects and small surface contamination of a pyrex tube is presented. The electron paramagnetic resonance sign als of nitroxide free radicals used as spin probes dispersed in the li quid give information both on the local microviscosity and on the prof ile of the droplets even in the case of very thin films. The sliding v elocity is recorded as a function of the molecular weight of the chain s and of the viscosity, and a third-power polynomial for the profile i s proposed.