Electrochemical Deposition
of Hollow N‑Substituted
Polypyrrole Microtubes from an Acoustically Formed Emulsion
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Abstract
We outline an electrodeposition procedure from an emulsion
to fabricate
novel vertically aligned open and closed-pore microstructures of poly(<i>N</i>-(2-cyanoethyl)pyrrole) (PPyEtCN) at an electrode surface.
Adsorbed toluene droplets were employed as soft templates to direct
polymer growth. The microstructures developed only in the presence
of both ClO<sub>4</sub><sup>–</sup> and H<sub>2</sub>PO<sub>4</sub><sup>–</sup> doping ions due to a slower rate of polymer
propagation in this electrolyte. Two sonication methods (probe and
bath) were used to form the emulsion, producing significantly different
microstructure morphologies. Control over microtube diameter can be
achieved by simply altering the emulsion sonication time or the amount
of toluene added to form the emulsion. Electrochemical characterization
indicated the PPyEtCN microtube morphology had an increased electrochemical
response compared to its bulk counterpart. TEM analysis of individual
closed-pore microtubes identified a hollow interior at the base within
which the toluene droplet was encapsulated. This cavity may be used
to entrap other compounds making these materials useful in a range
of applications. The methodology was also applied to form microstructures
of poly(3,4-ethylenedioxythiophene) and polypyrrole