Biomedical Engineering Reference
In-Depth Information
5
µ
m
29.2
µ
m
PtMB.264
0
10
20
µ
m
30
µ
m
FIGURE 2.21(a)
A scanning electron micrograph (SEM) of an IPMNC film sample treated
with a dispersing agent polyvinyl pyrolidone or PVP (top) and its x-ray line scan (bottom).
As can be seen, the Pt penetration is deeper, more homogeneous, and more consistent due to
the use of the dispersant.
1.0
0.8
D
eff
~1
×
10
-8
cm
2
/sec
0.6
10
-9
cm
2
/sec
D
eff
~1
×
0.4
0.2
10
-10
cm
2
/sec
D
eff
~1
×
0.0
0
5
10
15
20
25
30
δ
t
(
µ
m
)
FIGURE 2.21(b)
Profiles of platinum concentration versus depth penetration for different
diffusivity coefficients
D
eff
. As can be seen, the Pt penetration is deeper, more homogeneous,
and more consistent due to use of the dispersant PVP.
Q
t
,
PVP
/
Q
t
1.1. This means that the PVP-treated IPMNC consumes approximately
10% more charges. This raises a point that merely 10% increased consumption of
charges is not the only reason to increase the force density by as much as 100%.
An increase in force density of as much as 100% represents a very favorable
gain for a 10% increase in consumed charge. Therefore, it can be concluded that it
is the “granular damming effect” that minimizes the water leakage out of the porous
≅
