Electrochemical Synthesis and Characterization of Multi-walled Carbon Nanotubes/Polypyrrole and Polypyrrole Hollow Nanotubes

Abstract

We report the electrochemical synthesis and characterization of hybrid structures composed by hollow nanotubes of polypyrrole and core-shell composites of multi-walled carbon nanotubes (MWCNTs) coated by polypyrrole (PPy). The synthesis of these systems is critically dependent on relative concentration of carbon nanotubes (introduced as a template for polymerization) and affects the level of conductivity of media, the diameter and relative roughness of synthesized nanotubes. The competition induced by polymerization on the surface of different templates (aggregates of methyl orange and MWCNT) allows that smooth structures can be obtained, minimizing the synthesis of granules of polypyrrole, in a process that affects the morphology, thermal and electrical properties of synthesized materials. As a result, the impedance of mixed composite is lower than the other obtained for each system (MWCNT and hollow nanotubes of PPy), in an indication that synergistic interaction is favored during the synthesis.

Synthesis and Dielectric Characterization of Multi-walled Carbon Nanotubes/Polypyrrole/Titanium Dioxide Composites

“…As we can see, the homopolymer tends to aggregate in form of large globules with a characteristic porosity. MWCNT in the PPy/MWCNT system acts as a filler and contributes to the distribution of core/shell aggregates of CNTs/polypyrrole immersed in a globular distribution of polypyrrole (similar to that reported by us in a previous work) (15).…”

“…As we can see, an endothermic peak in the thermogram of pure PPy is verified at 78.6 C, which is attributed to the conformational changes in the polypyrrole chains (15,19). It is reported in the literature that inclusion of MWCNTs during chemical polymerization contributes with mechanical reinforcement of the resulting composite.…”