Controlled Electrochemical Synthesis of Conductive Polymer Nanotube Structures

Abstract

We have investigated the electrochemical synthetic mechanism of conductive polymer nanotubes in a porous alumina template using poly(3,4-ethylenedioxythiophene) (PEDOT) as a model compound. As a function of monomer concentration and potential, electropolymerization leads either to solid nanowires or to hollow nanotubes, and it is the purpose of these investigations to uncover the detailed mechanism underlying this morphological transition between nanowire and nanotube. Transmission electron microscopy was used to characterize electrochemically synthesized PEDOT nanostructures and measure the extent of their nanotubular portion quantitatively. The study on potential dependency of nanotubular portion shows that nanotubes are grown at a low oxidation potential (1.2 V vs Ag/AgCl) regardless of monomer concentration. This phenomenon is attributed to the predominance of electrochemically active sites on the annular-shape electrode at the pore bottom of a template. The explanation was supported by a further electrochemical study on a flat-top electrode. We elaborate the mechanism by taking into account the effect of electrolyte concentration, temperature, and template pore diameter on PEDOT nanostructures. This mechanism is further employed to control the nanotube dimensions of other conductive polymers such as polypyrrole and poly(3-hexylthiophene).

Conjugated Polymer and Hybrid Polymer-Metal Single Nanowires: Correlated Characterization and Device Integration

“…1.(b)]. A recent study [Xiao (2007)] has shown that the morphological transition between the two configurations can be explained by a mechanism based on monomer diffusion and reaction kinetics. Roughly, as exemplified in Fig.…”

Fabrication of Conducting Polymer Nanowires

“…Fu et al (2001) synthesized polythiophene nanowires on flexible gold film by electro-polymerization of thiophene in boron trifluoride diethyl etherate solution using an alumina membrane. The length and diameter of various conducting polymer nanowires synthesized using AAO templates can be controlled by polymerization time and current Park et al, 2005;Xiao et al, 2007). The electrical properties of conducting polymers were controlled through various synthetic conditions, such as doping level, dopant, and template-dissolving solvents .…”

Novel Nanomaterials for Clinical Neuroscience

“…As a result, novel nanomaterials are available that have decreased toxicity and increased biocompatibility compared to CNTs. For example, nanotubes made of conducting polymers, such as polypyrrole, polyaniline, poly (3-hexylthiophene), and poly(3,4-ethylenedioxythiophene) (PEDOT) can be synthesized by electrochemical polymerization on a porous surface (Xiao et al 2007). Although these nanotubes were initially applied in electronic devices (Xiao et al 2007), they also have significant potential in biomedical applications.…”

“…For example, nanotubes made of conducting polymers, such as polypyrrole, polyaniline, poly (3-hexylthiophene), and poly(3,4-ethylenedioxythiophene) (PEDOT) can be synthesized by electrochemical polymerization on a porous surface (Xiao et al 2007). Although these nanotubes were initially applied in electronic devices (Xiao et al 2007), they also have significant potential in biomedical applications. A recent study by D. C. Martin and colleagues developed conductive nanotubes, which can be electrically stimulated for a controlled release of drugs (Abidian et al 2006).…”