ELECTRICALLY CONDUCTIVE POLYANILINE POLY(VINYL ALCOHOL) COMPOSITE FILMS - PHYSICAL-PROPERTIES AND MORPHOLOGICAL STRUCTURES

Polyaniline (PAn)-poly(vinyl alcohol) (PVA) composite film prepared electrochemically has a gradient of PAn content along the thickness direction with some PVA chains grafted by PAn chains to various extents along the thickness direction. This composite film can be considered to be composed of four regions: a PAn layer, a PAn-rich region, a PAn gradient region, and a PAn-poor region. The composite film has conductivities on the film surface of the electrode side about equal to the conductivity of PAn at the same doping level and on the solution side lower than the conductivity of PAn by a factor of 10(4). As a result of the PAn content gradient and the presence of moisture, the bulk conductivity of the composite film drops significantly in the glass transition range of PVA. The chemically prepared composite film has a bulk conductivity lower than that of PAn by a factor of 10 with no significant variation in conductivity in the glass transition region of PVA and is featureless in morphology.