Conducting composite films of polyalkylanilines with nylon 6 as the insulating matrix were electrochemically synthesized and characterized. The electrochemical properties of the alkylanilines and their composites were investigated with a cyclic voltammetry technique. The magnetic properties of the polymers and composites were analyzed, and their conducting mechanisms were found to be of bipolaron nature. With Fourier transform infrared spectra, it was clarified that polymerization occurred via the -NH2 group in a head-to-tail mechanism. Through thermogravimetric analyses, the thermal properties of the polymers and their composites were elucidated. (C) 2002 Wiley Periodicals, Inc.