Disclosed herein is a composite film comprising a layer of an organic polymer, wherein the organic polymer is an elastomer; the organic polymer having an elastic modulus of less than or equal to about 10.sup.5 Pascals when measured at room temperature; and a bundle of carbon fibers disposed in the layer of organic polymer; each bundle comprising a column and an end face; each bundle also having a longitudinal axis that is substantially parallel to the column and passes through the center of the column; the end face of the carbon fiber bundle intercalated with nitrate ions and fibrillated so as to have a surface area measured perpendicular to the longitudinal axis that is about 110% to about 250% greater than the surface area of a cross-section of the carbon fiber bundle measured at the column.