Biomedical Engineering Reference
In-Depth Information
(A)
Polystyrene bead
Alumina membrane
(B)
SiO
2
film
(C)
Au/Ti seed layer
(D)
PPy synthesis in
nanopores with
exposed seed
layer
(E)
PPy nanowires
FIGURE 13.23
Fabrication sequence for electropolymerization of isolated polypyrrole nanowires.
(A)
(B)
FIGURE 13.24
SEM images of the isolated PPy(DBS) nanowire groups: (A) low-magnifi cation view and
(B) high-magnifi cation view of the nanowire attachment to Au conductive seed layer.
of the beads resulted in the exposed conducting layer at the bottom of some of the pores—in this
case, groups of pores with overall diameter of 500 nm (with 20 nm individual pores) and overall
density of one group per 100 µm
2
. PPy nanowires were then electropolymerized in those pores
where the gold conducting seed layer was exposed to the pyrrole monomer-NaDBS electrolyte solu-
tion. The alumina membrane was then dissolved in 0.5 M NaOH, and the resulting substrates held
isolated groups of 40 µm long PPy(DBS) nanowires (Figure 13.24A).
The nanowires appear to lie fl at on the SiO
2
substrate in the SEM images due to the dry-
ing of the sample with the surface tension of evaporating water pulling nanowires down to the
