Nanocrystalline carbon film electrodes generated and patterned by UV-laser ablation of polystyrene

A carbon conductive film consisting of nanometer sized domains has been patterned by scanning photoablation of polystyrene. The film formation involves the photoablation of a highly insulating polymer, and the redeposition of conductive carbon fragments. This film has been investigated by scanning electron microscopy, atomic force microscopy, microRaman spectroscopy, electrical conductivity and standard electrochemical measurements. Film deposition under different gas flow conditions has revealed major differences in the electrical and electrochemical properties of the material. Cyclic voltammetry and double layer capacitance measurements have indicated the formation of a conductive layer with a high specific area when generated in ambient atmosphere. Inert atmospheres like nitrogen and argon lead to conducting films with low double layer capacitance values (10 mu F cm(-2)), whereas an air atmosphere leads to conducting films with supercapacitance values (5 mF cm(-2)). This large difference in capacitances is discussed in terms of the photochemical effects of the ambient atmosphere during the polymer treatment.