SECM imaging of micropatterned organic films on carbon surfaces

Micropatterned carbon surfaces were prepared by electrochemical soft-lithography and imaged with scanning electrochemical microscopy. The technique allows the characterization of the surface in terms of resistance to molecules permeating the layer. Two types of electrogenerated organic layers were tested: sub-monolayers of tetraethyleneglycol diamine (TGD) and methylphenyl (MP) layers of variable thickness. TGD surfaces were found to provide little isolation and molecules can freely diffuse inside the layer to reach the surface. MP covered surfaces offer a much better resistance to organic molecules and can be almost insulating in the case of multilayer deposits. The blocking was found to be slightly better in water in agreement with the poor affinity of the aromatic layer with water.