Electropolymerization of methacrylonitrile on a rotating disk electrode at high spinning rate

The electropolymerization of methacrylonitrile has been performed under voltammetric conditions on a rotating disk electrode (RDE) spinning at high angular rotation rate (omega = 10000 rpm) in anhydrous acetonitrile. The analysis of the electrode surface by X-ray photoelectron spectroscopy (XPS) and ellipsometry reveals that a grafted film of polymethacrylonitrile is present on the surface at the end of the synthesis. In addition, the polymer known to result from a polymerization in solution, which is usually (i.e. at omega = 0) found on the surface before rinsing, is not present on the electrode. Estimations provided by the Navier-Stokes equation indicate that. at such high rotation rates, considerable convection effects are to be expected at distances from the surface of the order of 1 nm. These observations, combined with the fact that acetonitrile is an excellent solvent of polymethacrylonitrile, lead us to the proposal that the grafted polymer film is initiated directly on the surface, and may not result from an a posteriori precipitation of the polymer formed in solution. (C) 1999 Elsevier Science S.A. All rights reserved.