Chemistry Reference
In-Depth Information
d
n
1
r
3
n
g
|
7
3
.
Figure 6.3
Classifications of gels based on fibres and solvent. Gels can be either made
up of polymeric (below the horizontal line) or molecular gel fibres (above
the horizontal line). The solvent that makes up the majority of the gels
(by weight) can either be water (left: hydrogels) or organic solvent (right:
organogels). Molecular gels are also known as self-assembled or physical
gels.
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to the covalent bonds of polymeric gel fibres (e.g. poly(2-hydroxyethyl
methacrylate) PHEMA).
6.2.2.2 Molecular Gels in Nature
It is worth emphasising that self-assembling fibrillar structures are found in
nature, and although they do not form gels, their functional properties do arise
from their fibrillar nature rather than their building blocks per se. The most
recognisable examples of this kind are the b-amyloids that are associated with
diseases such as Alzheimer's disease.
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A few natural peptide and protein
hormones self-assemble into nondisease-related aggregates near or within their
storage sites.
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Finally, it is important to note that molecular gels are dynamic
in nature
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akin to naturally occurring self-assembling systems, such as actin
filaments and the above-mentioned b-amyloids. The dynamic nature of mo-
lecular gels allows them to adapt better to their environments and changes in
their surroundings, including inside living tissue. It is quite probable that the
dynamic nature of molecular gels is the underlying explanation for the apparent
