Conducting-polymer microcontainers: Controlled syntheses and potential applications

We have demonstrated the controlled synthesis of conducting-polymer microcontainers through the electrochemical generation of surfactant (i.e., beta-naphthalenesulfonic acid, beta-NSA)-stabilized H-2 gas bubbles on the working electrode, followed by electrochemical polymerization of pyrrole around the wall of the soap-bubble template. It was noticed that the density, shape, and wall thickness of the polypyrrole microcontainers thus prepared could be regulated by controlling the electrochemical potential applied for the generation of H-2 gas and the experimental conditions (e.g., the surfactant concentration, number of the cyclic voltammetric scanning) for the electropolymerization of pyrrole. By pre-patterning the working electrode surface with non-conducting polymers using microcontact printing (muCP) or plasma patterning, we have also produced conducting-polymer microcontainers in a patterned fashion. Furthermore, potential applications of the patterned and non-patterned conducting-polymer microcontainers have been demonstrated; for example, through the encapsulation of appropriate fluorescence-labeled molecules (e.g., fluorescein cadaverin) into the conducting-polymer microcontainers by sealing their opened mouths with sequential electropolymerization of pyrrole. The resulting closed microcontainers could then be used for controlled releases.