Biomedical Engineering Reference
In-Depth Information
200
m
µ
226
µ
m
SE/BSE, 8184000
PtMb, 36
PdLa 1, 66
0
100
200
µ
m
FIGURE 3.42
Concentration of Pt-Pd particles during chemical plating at a certain depth
away from the surface of IPMNCs.
Figure 3.44 shows typical AC impedance data of IPMNCs. For the typical
IPMNC artificial muscles, the importance of
R
ss
relative to
R
s
may be interpreted as
Σ
R
R
L
t
SS
≈>
1
(3.4)
S
where
t
is the thickness of the platinum surface electrode. Considering that the typical
value of
t
is ~1-10
m, equation (3.4) is valid. The equation states that significant
overpotential is required to maintain the effective voltage condition along the surface
of the typical IPMNC muscle. In other words, the voltage drop along the surface
electrode direction is appreciable. In fact, a typical set of data is shown in figure 3.45.
One way to solve this problem is to overlay a thin layer of a highly conducting
metal (such as silver or copper) on top of the platinum surface electrode. Figure
3.46 shows a schematic diagram of the typical silver (or copper) deposited IPMNC
µ
