Directing polypyrrole growth by chemical micropatterns: A study of high-throughput well-ordered arrays of conductive 3D microrings

An array of well-ordered conducting polypyrrole microrings doped with cobaltabisdicarbollide [Co(C2B9H11)2]− anions was fabricated by means of electropolymerization and submerged micro-contact printing techniques. The different conductive properties of the micropatterned thiols acted as a template for directing the electrochemical 3D growth of the microstructures over large areas. X-ray photoelectron spectroscopy characterization confirmed the presence of this unusual doping anion within the polymer. Its intrinsic properties together with hydrophobic interactions with the thiols guided the formation of the ring structures. A topographic study by atomic force microscopy gave insights into the PPy/[Co(C2B9H11)2]− growing mechanism which is in agreement with the theoretical model of metal growth. Finally, the conductive properties of the microstructures were addressed by conductive-atomic force microscopy, showing a highly conductive behaviour. This methodology using cobaltabisdicarbollide as dopant anion could have important applications in organic microelectronics for the development of biosensors, in cell microarrays and for the fabrication of polymer-based microencapsulators.