POLYMERS AT SOLID INTERFACES - A SPIN-LABELING APPROACH

Polymers physically adsorbed or chemically grafted on a solid surface can be studied at a microscopic molecular level by Electron Paramagnet ic Resonance (EPR) spectroscopy. The signal of nitroxide free radicals used as spin labels is sensitive to the Brownian motion of the segmen ts and generally shows lines characteristic of two different environme nts, the loops and tails in solution, and the trains on the surface. T he previsions of simple models for what can be expected from the measu rements are recalled. The relevance of the method is confirmed on line ar neutral chains in well defined situations. The technique is then ap plied to a number of new systems giving valuable information on the be haviour of the macromolecules in these more complex conditions.