Biomedical Engineering Reference
In-Depth Information
10
6
1.0M KCI
10
5
1.0M
TMAC
0.05M KCI
0.05M
TMAC
Water
Silicon oil
10
4
0
100
200
300
Time (min)
400
500
Plot of the storage Young
'
s modulus E
0
as a function of time for 2.0 wt% gellan gel immersed in
various salt solutions. The dotted line represents E
0
of gellan gels immersed in silicon oil. Here E
0
was measured by observing the longitudinal vibration of a cylindrical gel, a technique which helps
to eliminate the usual slippage effects. Reprinted with permission from Hossain and Nishinari
(
2009
) © 2009 Springer.
Figure 5.6
350
KCl
325
300
275
NaCl
250
−
1.6
−
1.2
−
0.8
log
c
salt
−
0.4
0
Dependence of the gelation temperature of
κ
-carrageenan gels on electrolyte concentration as
measured by optical rotation and light scattering: optical rotation, 0.25%
Figure 5.7
κ
-carrageenan (
○
); light
scattering, 1%
κ
-carrageenan (×). Reprinted with permission from Snoeren and Payens (
1976
)©
1976 Elsevier.
prediction by Record (
1967
). Since it is likely that counterions condense on to the
carrageenan chains, Snoeren and Payens estimated the slope by Manning theory
(Manning,
1988
) but still found a large deviation. They attributed this deviation to the
Debye
Hückel approach on which both the treatments of Record and Manning are based
(
Figure 5.7
).
-
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