Biomedical Engineering Reference
In-Depth Information
and fiber were placed about 1 cm from the stainless steel anode. Note that the spring
with the fiber was acting as the anode in this case.
The voltage was then turned on to 5 V for an approximate period of 1 min. The
fiber was then measured. Following this, the polarity was switched and the spring
electrode with the fiber became the cathode. Again, after 1 min at 5 V, the length of
the fiber was measured.
4.3.7.1
Results
It was found that PAN fibers that had been boiled in lithium hydroxide, used with a
0.1-
N
sodium chloride electrolyte solution, had the best response to electrical activa-
tion (see table 4.4 and fig. 4.33). These fibers, initially 1 in. long, expanded on average
about 30%, to 1.3 in. when placed in the solution. After acting as an anode for 1 min
at 5 V, the fibers, on average, were reduced in size to about 0.85 in. Then, as the
fibers acted as cathodes, they increased in length to, on average, 1.05 in.
In contrast, fibers that had been boiled in lithium hydroxide and used with a 0.1-
N
LiOH solution did not do so well with electrical activation (see table 4.5 and fig. 4.34).
TABLE 4.4
LiOH PAN in NaCl Solution
Initial
length (in.)
Initial
expansion (in.)
After being
anode (in.)
After being
cathode (in.)
Trial 1
1.000
1.200
0.938
1.188
Trial 2
1.000
1.380
0.938
1.188
Trial 3
1.000
1.100
0.875
1.063
Trial 4
1.000
1.200
0.750
0.875
Electrical activation of PAN fibers (LiOH) in NaCl
1.600
1.400
1.200
1.000
0.800
0.600
Trial 1
Trial 2
Trial 3
Trial 4
0.400
0.200
0.000
Initial
length (in.)
Initial
expansion (in.)
After
being anode (in.)
After being
cathode (in.)
FIGURE 4.33
Electric activation of PAN fibers (LiOH) in NaCl.
