For synthesis polyacrylamide/TiO2 composite hydrogels was used aqueous TiO2 nanosuspensions (Evonik-Degusa P25). It is known that nanoparticles in aqueous medium tend to aggregation. In the hydrogel mesh aggregation is enormous, reaching several tens of microns (see figure from optical microscope).
How to determine the shape and structure of this aggregates? How to calculate the aggregation degree ?
SEM will not work, because requires a vacuum (hydrogels lose their soft structure even when they are lyophilized).
Confocal microscopy is probably suitable ...
Small-angle X-ray scattering and cryomicroscopy can be used for such systems. These devices are expensive and not widely available. Try CEM. On the substrate, get a dried sample. Polyacrylamide can "burn:", but maybe not. Apply the fractal theory to the system opion. Look at our article on the synthesis of nanoparticles of cobalt and manganese and an attached article.
One suggestion might be curing the hydrogel sample in a resin for 2 or 3 days and then slicing with the microtome and then observing the aggregations using TEM (I think that this method is very common for biological samples).
I have used this method successfully for imaging the calcium phosphate crystals inside the hydrogels.
Article Obtaining new composite biomaterials by means of mineralizat...
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