Electrodeposition of composite iron oxide–polyelectrolyte films

Composite films consisting of iron hydroxide and cationic polyelectrolytes, such as poly(diallyldimethylammonium chloride) and polyethylenimine were obtained via cathodic electrodeposition. Films up to several microns thick were obtained on Ni, Pt, graphite and carbon fiber substrates. By varying the concentration of the polyelectrolytes in solutions and deposition time, the amount of the deposited material and its composition can be varied. Heat treatment of the composites at 400°C resulted in formation of iron oxide films. The deposits were studied by thermogravimetric analysis, X-ray diffraction analysis and scanning electron microscopy. The mechanisms of electrochemical intercalation of the cationic polyelectrolytes into iron hydroxide deposits are discussed.