Chemistry Reference
In-Depth Information
Fig. 7.2
Formation of organosilicate colloids with
a
hydrolysis and
b
condensation and aging
7.2
Biohybrid Materials
In the case of silicate based biohybrid materials, the best control is obtained if the
two components are soluble in a single or a simple co-solvent system. For example,
in the case of the research within our own laboratory, we have been able to achieve
well behaved and robust bioorganic-inorganic hybrid formulations using sol gel
techniques that produce silicate colloids with long-term aqueous stability. A typi-
cal scheme demonstrating the formation of an epoxide decorated silicate colloid
is shown in Fig.
7.2
. Our approach has allowed for the formation of hybrids by
the combination of these preformed aqueous silicate colloids with water-soluble
polysaccharides providing access to good control over the properties of the final
biohybrid material.[
10
]
Forming a silicate colloid with a prescribed organic functionality on its surface
has been shown to provide a convenient and robust method for formulating a range
of interesting materials. Using a range of short chain organic crosslinking agents,
we have demonstrated the utility of this approach in the formulation of several cor-
rosion resistant coating systems,[
11
,
12
] as a pH responsive controlled release mate-
rial,[
13
,
14
] as a means of controlling the structure in a nanodimensional multilayer
device,[
15
] as a stabilizing host for controlling metal nanoparticle materials,[
16
]
and in fabricating a passive sampling device for metal ions in the environment.[
17
]
The initial idea behind these materials was to combine the durability of a silicate
material with the convenient reactivity of epoxy-amine organic reactions. However,
in addition to the utility of this approach, our work has also demonstrated that the
small organic crosslinking agents were responsible for significant aspects of the
physical and chemical properties of the resulting hybrid. In particular, the indi-
vidual strength of the nucleophile and the crosslinker size contributed to the extent
of epoxy-amine crosslinking and thus the degree of interaction between the hybrid
material components.[
11
] Based on these findings and their interesting contribution
to the properties of the resulting hybrid material, we were motivated to explore hy-
brids based on much larger organic species, particularly ones which would provide
