SOLVENT EFFECT ON THE ELECTROGRAFTING OF ACRYLONITRILE ON NICKEL

The effect of solvent on the reductive electrografting of acrylonitril e (AN) onto nickel cathodes has been studied in dimethylformamide (DMF ), a solvent for polyacrylonitrile (PAN), and in non-solvents that inc lude acetonitrile (ACN), propylene carbonate (PC) and pyridine (PY). E lectrografting responsible for the cathode inhibition has been observe d for the first time in PC and PY. Not only the polymer-solvent intera ctions but also the intrinsic polarity of the solvent have an effect o n the intensity of the inhibition peak which is the signature of the e lectrografting reaction. Concentration of the monomer in the electrode double layer appears to decrease as the solvent polarity is increased , consistently with a more efficient displacement of the monomer by a more polar compound. That such a competition occurs is also supported by the effect of the nature and concentration of the conducting salt. The best quality films are formed in DMF, which is a solvent for PAN. Quartz microbalance experiments have emphasized the crucial importance of the potential range used for the AN electroreduction, particularly in a solvent of the polymer. (C) 1998 Elsevier Science S.A.