Biomedical Engineering Reference
In-Depth Information
2.0
Nafion
TM
-117; Cation = Li
+
; Reducing agent = LiBH
4
;
1V Step; 1/2 Hz
Width = 7.2 mm; Effective length = 16.0 mm;
(Note that F
max(sample #28)
~0.35 g-force)
1.5
Norminal process
1.0
0.5
0.0
02
135
4
678
9
112131415161718192021222324252627282930
Sample number
FIGURE 3.17
A comparison of blocking forces for 29 different Taguchi samples.
that interacts with the polymer matrix. The electric responses of the Taguchi samples
were also investigated and are presented here in terms of the consumed amount of
charges (current,
I
, vs. time) at applied step voltages of 1, 2, 3, and 4 V for two
important samples: 3 (the best performance) and 28 (baseline).
Overall, the current responses were capacitive. This behavior may be attributed
to the double layers adjacent to platinum particles or proximate metallic layers. Also,
as we increase the applied voltages, the charge consumption is significantly increased
(see figs. 3.20 and 3.21). This means the IPMNC materials utilize charges but also
store them within the materials. Further study is to investigate such an effect.
Note in figures 3.19(a) and 3.19(b) that the actual normal stress,
σ
N
, and normal
ε
N
, stress-strain curves for IPMNCs lie somewhere between the normal stress,
σ
N
, and normal strain
strain,
ε
N
, stress-strain curves for the wet and the dry Nafion ionomer
samples.
3.3.4
E
FFECTS
OF
D
IFFERENT
C
ATIONS
Realizing that the properties of IPMNC base material (polymer) differ depending
upon different cations, IPMNC test samples were prepared by the processes
described in the previous section with different cations. First, a batch of the IPMNC
artificial muscle of dimensions of 10
×
20 cm was prepared with platinum. Then,
