Electropolymerization of methacrylonitrile on a rotating disk electrode athigh spinning rate

The electropolymerization of methacrylonitrile has been performed under vol tammetric conditions on a rotating disk electrode (RDE) spinning at high an gular rotation rate (omega = 10000 rpm) in anhydrous acetonitrile. The anal ysis of the electrode surface by X-ray photoelectron spectroscopy (XPS) and ellipsometry reveals that a grafted film of polymethacrylonitrile is prese nt on the surface at the end of the synthesis. In addition, the polymer kno wn to result from a polymerization in solution, which is usually (i.e. at o mega = 0) found on the surface before rinsing, is not present on the electr ode. Estimations provided by the Navier-Stokes equation indicate that. at s uch high rotation rates, considerable convection effects are to be expected at distances from the surface of the order of 1 nm. These observations, co mbined with the fact that acetonitrile is an excellent solvent of polymetha crylonitrile, lead us to the proposal that the grafted polymer film is init iated directly on the surface, and may not result from an a posteriori prec ipitation of the polymer formed in solution. (C) 1999 Elsevier Science S.A. All rights reserved.