Biomedical Engineering Reference
In-Depth Information
were formed by rinsing away PMMA homopolymer in a selective
solvent (acetic acid) such that the polystyrene matrix remained
non-cross-linked and could be removed by simple dissolution to
produce freestanding polymer nanowires (Fig. 2.14).
February 8, 2010 17:21
PMMA
homopolymer
(a)
(b)
(c)
PS-b-PMMA
PS-r-PMMA
conducting polymer
(d)
(e)
Figure 2.14
Schematic fabrication of conducting PPy polymer nanowires
from PS-
-PMMA templates on neutralized ITO glass substrates. Reproduced
with permission from Ref. [79].
b
Li
et
al.
produced
polyaniline
(PANI)
nanowires
by
-P2VP
nanoporous film on a gold substrate. Growth nucleated only in
the pores created after selective dissolution of the minority P2VP
chains in ethanol. Nanowires with diameters of 30-40 nm continued
to grow out of the template where they entangled to form a highly
porous film.
electropolymerization in the pores of a 22 nm thick PS-
b
2.4.5 Combinaion with Top-Down Lithography
Nanometer-scale patterning using block copolymer microphases
can easily be integrated with micrometer scale top-down
lithographic techniques. The most straightforward method is simple
patterning of the conducting working electrode before coating the
copolymer film. For example, Tseng
et al.
patterned a conducting
ITO substrate supporting a poly(styrene-
-poly(L-lactide)) film and
electrodeposited Ni metal nanowires only from these conduction
regions [59]. This method is well suited to polymers because of the
b
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