“…While graphite and, in particular, carbon black are usually not categorized as polymers, they share some of their properties with respect to their extended carbon backbone. For their high electrical conductivity, biological inertness, low price and easy handling, they are excellent filler materials for creating flexible, voluminous conductor tracks or coatings with silicones or polyurethanes as the matrix (Calixto et al, 2007;Huang et al, 2011). As with any conductive filler (e.g., antimony-or indium-doped tin oxide, silver (Ahn et al, 2009;Gong & Wen, 2009;Larmagnac et al, 2010;Zhang et al, 2011), carbon, or any form of their nanoparticle derivatives (Sekitani et al, 2009;Pavesi et al, 2011)), a conductive polymer can be generated when the percolation threshold 17 of the filler has been surpassed (Kirkpatrick, 1973;Milliken and Company, 1997).…”