Fabrication of porous carbon micropillars using a block copolymer as porogen

A technique to fabricate porous carbon micropillars using a block copolymer, F127, as porogen is described. In this process, negative tone photoresist (i.e. SU-8) mixed with F127 was photopatterned and carbonized under inert atmosphere. The thermal behavior of the photoresist precursor (F127 + SU-8) during carbonization process was characterized using differential scanning calorimetry and thermogravimetric analysis. Texture analysis on the carbon surface showed a mesoporous feature distribution. Electrochemical characterization based on the reaction of Fe(CN)63-/Fe(CN)64- redox couple was utilized to study the change in the effective surface area (Aeff) of the porous carbon electrodes with different weight percentages of F127 in SU-8. These results indicated that porous carbon thin film electrodes derived from 10% F127 mixed in SU-8 had an Aeff 185% compared to the conventional photoresist derived carbon electrode. This fabrication approach can be employed to produce reproducible high aspect ratio carbon microelectrodes with different shapes for various electrochemical devices.