The patterning of conductive substrates by polymer brushes may be achieved by using Successively scanning electrochemical microscopy (SECM) and atom transfer radical polymerization (ATRP) After the. surface functionalization by a brominated aryldiazonium initiator, SECM allows the local reduction at the micrometer scale of the initiator grafted layer. Different channels sizes involved in charge transport within the initiator layers are evidenced by combining SECM, CV and observation of the aryl-grafted layer transformation. ATRP is performed on the SECM patterned substrate. Inside the pattern, the lower density of initiator decreases the polymer thickness. The pattern resolution is enhanced when the direct mode of the SECM is used instead of the mediated indirect mode. (C) 2009 Elsevier Ltd. All rights reserved.