Stimuli responsive microgels decorated with oligoglycidol macromonomers: Synthesis, characterization and properties in aqueous solution

In this work we focused on synthesis and characterization of aqueous poly(N-vinylcaprolactam) (PVCL) microgels decorated with oligoglycidol-macromonomers. Oligoglycidol macromonomers with styrene or acrylate polymerisable group and tunable length of the oligoglycidol chain (6, 12 and 50 glycidol units) were synthesized. The microgels were synthesized by aqueous precipitation copolymerization of N-vinylcaprolactam and oligoglycidol macromonomers in presence of crosslinking agent. The length of the oligoglycidol chain and the concentration of macromonomer in the reaction mixture were varied to investigate a direct influence on the polymerization rate and microgel properties. Synthesized microgels exhibit radii from 50 to 350 nm and show temperature-responsive properties. We demonstrate that oligoglycidol macromonomers are localized predominantly on the microgel surface. This ensures excellent colloidal stabilisation of oligoglycidol-decorated microgels in aqueous solutions and functionalization of microgels with hydroxyl groups, which can be potentially used for further post-modification reactions.