Biomedical Engineering Reference
In-Depth Information
NaOH
1.4
0.5 N solutions
0.5 N solutions
0.5 N solutions
1.2
1.0
1 N solutions
0.8
1 N solutions
0.6
1 N solutions
2 N solutions
0.4
2 N solutions
0.2
2 N solutions
0.0
1
2
3
4
5
Measurement #
FIGURE 4.28
PAN fiber length change (sodium hydroxide and HCl).
O
N
O
O
N
C
O
C
C
O
N
Li
+
C
N
OH
Li
+
O
HO
O
O
N
C
N
C
Li
+
O
OH
FIGURE 4.29
PAN elongation behavior explained by the osmotic behavior.
4.3.5
E
LECTRIC
A
CTIVATION
OF
PAN F
IBERS
The effort was to design and fabricate a spring electrode configuration (fig. 4.31)
by using thin conductive wires (fig. 4.30) in a helical spring configuration with the
PAN fiber encased in the middle. The whole assembly was encased inside a flexible
membrane with some printed or embedded electrodes on the inside wall of it. Design
issues were to first find the spring constants of both electrodes and the selection of
membrane materials. Also, a conceptual development of hybridizing PAN and
IPMNC for contractile fibers was recommended by ERI technical staff and was
initiated at ERI laboratories.
4.3.6
A
DDITIONAL
R
ESULTS
PAN fibers were oxidized at 220
C for 90 min in air. In the first experiment, these
fibers measured at 1 in. in length; each was activated in boiling 1
N
KOH for 30
mins. The fibers were then soaked in distilled water for 30 min in order to obtain a
base length. Then, several fibers were placed in each of 0.5, 1, and 2
N
KOH for 30
min and measured. Next, the fibers were again put into distilled water for 30 min
and then measured. Following this, the fibers were soaked in 0.5-, 1-, and 2-
N
HCl
solutions (corresponding fibers from the alkaline—for example, fibers from the 0.5
°
