Monodisperse thermoresponsive microgels of poly(ethylene glycol) analogue-based biopolymers

Monodisperse microgels of P(MEO2MA-co-OEGMA) have been synthesized by using free radical polymerization. Microgels with a variety of particle radii ranging from 82 to 412 nm have been obtained with different surfactant concentrations. The particle size distribution is extremely narrow and even better than that for PNIPAM microgels. Pure MEO2MA microgels have an LCST of about 22 degrees C. The LCSTs corresponding to the molar ratio of OEGMA to MEO2MA at 10 and 20% are 31 and 37 degrees C, respectively. Microgels in water self-assemble into various phases, including a crystalline phase with iridescent colors, which are the result of Bragg diffraction from differently oriented crystalline planes. Considering that PEG is nontoxic and anti-immunogenic as proven by the FDA, thermoresponsive P(MEO2MA-co-OEGMA) microgels may have many exciting biomedical applications.