Abstract: Electrically conductive polymer materials, such as mixtures of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrenesulfonate) (PSS) are combined with functionalized carbon nanotubes to form composites that exhibit increased electrical conductivity. Functionalized or non-functionalized carbon nanotubes combined with the same electrically conductive polymer materials are combined with non-conductive polymers to increase the electrical conductivity of the non-conductive polymer. The functionalized carbon nanotubes are functionalized with carboxyl and/or hydroxyl groups. The resulting materials are useful in methods of forming electrically conductive films and electrically conductive features.