Biomedical Engineering Reference
In-Depth Information
2-pan01 1.0 kV 10.8 mm
×
2.50k SE(M) 5/31/02
20.0 um
FIGURE 4.13
Activated PAN at a low-pH condition (1
N
HCl).
9-pan01 1.0 kV 10.8 mm
×
300 SE(M) 5/31/02
100 um
FIGURE 4.14
Activated PAN at a high-pH condition (1
N
NaOH).
rough (fig. 4.19). This salt layer may act as a mass transfer resistance for actuation.
Therefore, when the pH is reversed, such a salt layer may dominate the response
time of the PAN muscles.
Figures 4.20 and 4.21 show the raw nano-PAN fibers. Such fibers have a dimen-
sion of 250-300 nm diameter. These fibers were produced by an electrospinning
technique based on joint collaborative research and development between ERI and
Santa Fe Science and Technology (SFST) Corporation.
In figures 4.22 and 4.23, the activated nano-PAN fibers under a low pH condition
HCl) are presented. As can be seen, the nano-PAN fibers were stuck together and
deformed (“solvated” deformation) and lost their mechanical stability. This could be
due to the lack of polymer cyclization with low dehydrogenation. A high-temperature
heating process (220
(1
N
C) may enhance polymer cyclization and the close-
chain system so as to increase mechanical strength of the nano-PAN fibers.
°
C <
T
< 250
°
