Pickering emulsions stabilized by thermoresponsive oligo(ethylene glycol)-based microgels: Effect of temperature-sensitivity on emulsion stability

The stability of emulsions stabilized by soft and responsive microgels their macroscopic properties are governed the microstructure microgels, in particular deformability. However, little is known about role microgel chemistry, though it expected that polymeric backbone with an amphiphilic structure a requirement for adsorption at oil-water interface. A series biocompatible, thermoresponsive poly(oligoethylene glycol)methacrylate (pOEMA) synthesized, varying hydrophobic-hydrophilic balance, or equivalent volume phase transition temperature (VPTT). Their behavior bulk solid interfaces compared to liquid interfaces, studied on flat model pendant drop method, drops, microgel-stabilized emulsions. Controlling composition simply changing number ethylene oxide groups hydrophilic side chain allows precise tuning VPTT range 20–60 °C. Simultaneously, swelling ratio deformability increase increasing hydrophilicity, as result polymerization process. Regardless all swollen pOEMA adsorb interface stabilize emulsions, whose flocculation state mechanical depends Unexpectedly, most remain stable upon heating above microgels. Such feature highlights extreme robustness, origin discussed. This study opens new opportunities use biocompatible Pickering emulsifiers.