Biomedical Engineering Reference
In-Depth Information
Pt particles within the IPMNC
(w/o PVP treatment)
Pt particles within the IPMNC
(with PVP treatment)
70.00 nm
70.00 nm
0.30
µ
m
0.30
µ
m
FIGURE 2.20(b)
TEM micrographs of two samples of IPMNC with and without PVP treat-
ment. Note how the addition of polyvinyl pyrolidone (PVP) causes the nanoparticles of
platinum to not coalesce and create a uniform and fairly homogeneous distribution of particles.
This is believed to create more uniform internal electric fields and cause the increased force
capability of IPMNCs and IPCNCs.
for the improved IPMNC. This situation is somewhat complicated due to the simul-
taneous effect of a mass transfer and significant kinetics; nevertheless, the estimated
value of
D
eff
= 1
10
-8
cm
2
s
-1
would be a convenient value for engineering design
of the platinum metallization process described here for the improved IPMNC.
In figure 2.22, the results of potentiostatic analysis are presented. The variation
of current following the application of an electric potential to the IPMNCs (the PVP-
treated IPMNC and the conventional IPMNC) is shown. The current decays expo-
nentially. The charge transfer after time
t
(
Q
t
) is
×
t
∫
QI dt
t
=
t
0
It is useful to make a direct comparison between
Q
t,PVP
(for the PVP-treated IPMNC)
and
Q
t
(for the conventional IPMNC). The data shown in figure 2.22 give
