We present a low-potential method to control surface roughness of doped polypyrrole through redox-induced transformation in surface morphology. By varying the electric potential of as-deposited doped polypyrrole in aqueous sodium dodecylbenzene sulfonate (0.1M) from -0.6 to +1.5V (vs. Ag/AgCl), doped polypyrrole transforms from being a hydrophilic film (60° contact angle) to a hydrophobic film (107° contact angle). Atomic force microscope measurements verify that the surface morphologies of doped polypyrrole, when subject to applied potentials from -0.6V to +1.5V, change from smooth (average roughness of 3.1 nm) to rough (average roughness of 31.1 nm), representing a 10-fold increase in surface roughness. Based on these evidence, we postulate that the degree of oxidation strongly influence surface roughness.
Date of creation, presentation, or exhibit
Department, Program, or Center
Microsystems Engineering (KGCOE)
Teh, K. and Lu, Yen-Wen, "Surface nanostructuring of biocompatible polymer for wettability control in MEMS" (2008). Accessed from
RIT – Main Campus