Biomedical Engineering Reference
In-Depth Information
O
O
O
NH
HN
O
34
O
O
H
H
N
N
O
N
N
O
H
H
O
O
O
O
O
NH
HN
O
35
O
O
H
H
N
N
O
N
N
H
O
H
O
O
O
O
NH
HN
O
O
36
O
O
H
H
N
N
N
O
O
N
H
H
O
O
O
O
O
NH
HN
O
37
O
O
H
H
N
N
N
O
H
O
H
O
O
Figure 1.26 LMOG
s used with the van't Hoff equation to assess toluene gel properties.
Reprinted with permission from Ref. [88]. Copyright 2008 American Chemical Society.
Kamlet-Taft parameters [90] have been used to determine the influence of
solvent type on the ability of a series of l-lysine
bis
-urea gelators [44]. In this
treatment, the H-bond donating and H-bond solvent acceptor parameters of the
Hamlet-Taft treatment are used to assess the degree to which the gelator can
establish an H-bonding network (because the urea fibers rely on H-bonding
networks among the urea gelator molecules), and the polarizability parameter
is assumed to be related to the solvation of the
n
-alkyl groups of the gelator
near its molecular ends. Thus, the sum of the H-bonding factors is implicated
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