Degradable microgels synthesized using reactive polyvinylalkoxysiloxanes as crosslinkers

Abstract

In the present work we demonstrate the synthesis of degradable thermo-sensitive poly(N-vinylcaprolactam) microgels via precipitation polymerization using reactive polyvinylalkoxysiloxanes as crosslinkers (Cross-PAOS). These compounds were synthesized by co-condensation of vinyltriethoxysilane and tetraethoxysilane followed by transesterification with poly(ethylene glycol) monomethyl ether (PEG) to increase their water solubility. Experimental results showed that the microgels synthesized using Cross-PAOS exhibited excellent colloidal stability in water. These microgels are thermo-responsive and their size can be tuned depending upon the ratio of vinyl and PEG groups in Cross-PAOS. The size of microgel particles increases with increasing vinyl groups in Cross-PAOS while it decreases with increasing PEG groups. The presence of silicon dioxide in the microgel structure was confirmed by X-ray photoelectron spectroscopy and elemental analysis. Additionally, the microgels prepared in this way contain crosslinking sites which can be degraded under alkaline conditions.