FORMATION AND CHARACTERIZATION OF COVALENTLY BOUND POLYELECTROLYTE BRUSHES

Poly(4-vinylpyridine) (PVP), functionalized at one terminus with a sty renyl group, was end-grafted to vinyl-functionalized self-assembled mo nolayers by UV irradiation in 1-methyl-2-pyrrolidinone. In this solven t and with oxygen excluded, surface reactions appeared to be selective ly limited to the polymer terminus. The dry film thickness was determi ned by ellipsometry and the grafted amount by FTIR-ATR (Fourier transf orm infrared spectroscopy in attenuated total reflection). Controlled amounts of positive charge were introduced into the grafted chains by alkylation with a 2.5% solution of CH3I in dimethylformamide (DMF). FT IR-ATR was used to quantify the extent of alkylation, from 10% to 96%. These polyelectrolyte brushes will comprise a model system for studyi ng polyelectrolytes at surfaces.