One aspect of the invention relates to a linker-free, one-step method of grafting polymer films onto organic substrates, and the films obtained by such a method. In certain embodiments, the grafted polymer films are conductive. In certain embodiments, said grafting method utilizes the ability for Friedel-Crafts catalyst to form radical cations from organic substrates. In one embodiment, the method provides poly-3,4-ethylenedioxythiophene (PEDOT) thin films grafted to organic substrates. In other embodiments, the method is applicable to the polymerization of other monomers to yield conducting polymers, such as polyanilines, polypyrroles, polyfurans, polythiophenes and their derivatives. Remarkably, the polymer films grafted by the inventive methods show enormous increases in adhesion strength. Further, in certain embodiments, polymer patterns were easily obtained using the inventive methods and soft lithography techniques. In certain embodiments, well-defined high-density line-and-space patterns were successfully obtained. In certain embodiments, e.g., when the polymer film is conducting, the obtained conducting polymer pattern grafted on common organic substrates can be used for integrated circuitry in flexible electronics.