STRUCTURAL CONFIGURATIONS OF THIN DRIED POLYANILINE FILMS ON GOLD(111) FROM SCANNING-TUNNELING-MICROSCOPY

The early stages of growth of polyaniline films electrodeposited on Au were studied by conventional electrochemical techniques, X-ray diffra ction and ex situ scanning tunneling microscopy (STM). From high resol ution STM imaging it appears that the first step of polyaniline format ion involves the adsorption of aniline monomers on Au(lll) terraces le ading to domains with hexagonal arrays involving a phenyl-phenyl dista nce in the range 0.70 nm less than or equal to d less than or equal to 1.0 nm. The second step corresponds to the initiation of the polymer growth yielding typically 10 x 10 nm(2) crystalline domains consisting of either 0.45 x 0.6 nm(2) rectangular arrays or 0.75 x 0.45 nm(2) ar rays forming 120 degrees angles. The crystalline domains coexist with highly disordered polymer domains. At advanced stages of growth, the f ormation of polymer fibers 2 nm in average width takes place leading t o a full substrate coverage by a polymer deposit with an irregular sur face. Copyright (C) 1996 Elsevier Science Ltd