High electrochemical active free-standing multiwalled carbon nanotube (MWNT) films have been synthesized from aniline oligomer functionalized MWNTs (MWNT-AO), by using filtration of the acidic phosphate ester (APE) doped MWNT-AO dispersions. The homogeneously distributed MWNTs endowed APE/MWNT films automatically releasing from the filter membrane. The sheet resistivity of MWNT-AO (850 Ω sq−1) showed a lower value than that of carboxyl MWNTs (1273 Ω sq−1), due to the doping effect of MWNT on aniline oligomer, confirmed by the N1s X-ray photoelectron spectrum. However, it showed a higher sheet resistivity value of 1526 Ω sq−1 after further doped by APE, because of the presence of unreacted dopant. After removing the residual insulating dopant by the vacuum filtration, the resultant APE/MWNT films showed the sheet resistivity value as low as 131 Ω sq−1. Thermogravimetric analysis showed that the MWNT loading in the film can be over than 77%, which showed the specific capacitance as high as 249 F g−1. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40259.