Role of Biopolymers in Sol-Gel Processing

A mixture of amylase and amylopectin with ratio of about 1 4 

One ofthe main reasons for the catalysis of reactions represented by Equations (2)-(4) is based on the fact that there was no j ellification ofthe solutions with biopolymers in the neutral region after a month. When the processes could also proceed with the addition of an acid or alkali in the absence of biopolymers, one could observe a drastic acceleration. The gelation time could be decreased from hours to a few minutes once polysaccharides and proteins were added. 

The next important role of biopolymers in the processes after precursor nucleation is that their macromolecules can serve as a template for silica. This has been 

Mica + Monolayer Mica + Monolayer Mica + Monolayer 

The silica nucleated only on the biomacromolecules. By decreasing the THEOS amount in solution from 3 to 0.03 wt.%, we observed a curtailment of the particle diameter to the macromolecular dimension. This constitutes evidence that most of the silica generated in situ was used to form a shell. 

---