PROOF Copyright Ó The Chemical Society of Japan Chemistry Letters Vol.36, No.10 (2007) 2 Surface Grafting of Polypyrrole onto Silicon Wafers Noncovalently bound Ppy patterns have high conductivity (low resistivity) before doping and brittle characteristics. However, the covalently grafted Ppy pattern shows relatively low conductivity and sticky viscoelastic properties. Daewon Sohn, Hyoseung Moon, Michael J. Fasolka, Naomi Eidelman, Sang-Mo Koo, Curt A. Richter, SeungEun Park, J. J. Kopanski, and Eric Amis Electronic Supporting Information CL-070789