A multi-step template-assisted approach for the formation of conducting polymer nanotubes onto conducting polymer films†
After exhibiting the important limitations of the template-assisted approach when electropolymerization on simple stainless steel electrodes and electrospinning of insulating polymeric templates are combined, hollow poly(3,4-ethylenedioxythiophene) (PEDOT) nano- and microtubes have been successfully prepared using an alternative approach. In this procedure, which is based on a two-step electropolymerization process, electrospun fibers are collected onto a relatively flat PEDOT film that plays a crucial role in complete coating of the template in the second electropolymerization process. Once the insulating fiber templates have been eliminated by solvent etching, the ability to exchange charge reversibly of the resulting hollow tubes is very similar to that observed for films while the amount of the electroactive surface is noticeably higher. The diameter and density of hollow tubes can be easily controlled through this multi-step template-assisted approach, allowing to collect such PEDOT structures onto simple steel electrodes. The multi-step strategy overcomes the limitations of the conventional approach, which was restricted to the use of neural electrode sites and restricted to applications related with neural prostheses, opening the door to the use of PEDOT hollow nano- and microtubes in many important applications, as for example the detection of biomolecules and the fabrication of organic and bio-organic batteries.