posted on 2022-07-08, 18:35authored byBabloo Sharma, Susanne Striegler
The development of macromolecular catalysts from polymerizable
monomers and ligands in miniemulsions requires the use of surfactants
and hydrophobes for the stabilization of droplets before polymerization
and for the solubilization of the obtained particles thereafter. In
order to elucidate the contributions of the chosen surfactants on
the catalytic performance of the synthesized macromolecular catalysts,
a systematic study was performed. Thereby, a correlation between nature,
polarity, and critical micelle concentration of nonionic surfactant
blends, the size of the resulting polyacrylate gels, and their performance
during catalytic glycoside hydrolyses was demonstrated. A catalytic
efficiency of up to 0.35 min–1 M–1 and a catalytic proficiency of up to 1,300,000 were observed for
an optimized, translucent gel in HEPES buffer at pH 7. The catalytic
efficiency was furthermore found to depend linearly inversely on the
hydrodynamic diameters of the polyacrylates. The gels were synthesized
in selected surfactant blends with critical micelle concentrations
that are different by more than 2 orders of magnitude. The results
of the study emphasize an overall critical need for a careful surfactant
selection during development of micro- and nanogel catalysts.