Biomedical Engineering Reference
In-Depth Information
Pt
5
µ
m
IPMC
Pt
5
µ
m
5
µ
m
IPMC
FIGURE 2.5
Two schematic diagrams showing different electrode penetration and manufac-
turing processes.
Note in figure 2.5 that the top left-hand part is a schematic showing the initial
process of making the ionic polymer metal nanocomposite. The top right-hand
section shows its top-view SEM micrograph, while the bottom left-hand side shows
a schematic of the process of depositing surface electrodes on the ionic polymer.
The bottom right-hand side shows its top-view SEM micrograph where platinum
deposited is predominantly on top of the initial Pt layer.
The initial compositing process requires an appropriate platinum salt such as
Pt(NH
HCl in the context of chemical reduction processes similar
to those evaluated by a number of investigators, including Takenaka et al. (1982)
and Millet (1989). The principle of the compositing process is to metalize the inner
surface of the material by a chemical-reduction means such as LiBH
)
HCl or Pd(NH
)
3
4
3
4
.
The ionic polymeric material is soaked in a salt solution to allow platinum-containing
cations to diffuse through via the ion-exchange process. Later, a reducing agent such
as LiBH
or NaBH
4
4
is introduced to platinize the material.
As can be seen in figure 2.6, the metallic platinum particles are not homoge-
neously formed across the membrane but concentrate predominantly near the inter-
face boundaries. It has been experimentally observed that the platinum particulate
layer is buried microns deep (typically 1-20
or NaBH
4
4
m) within the IPMNC surface and is
highly dispersed. The fabricated IPMNCs can be optimized to produce a maximum
force density by changing multiple process parameters. These parameters include
µ
