Synthesis and Characterization of Core-Shell Thermo-Responsive Microgels with Linear Transition Behavior

Thermo-responsive microgels with core-shell structure were prepared by free radical emulsion polymerization. The core of microgels was consisted of poly (N-isopropyl acrylamide) (PNIPAM), while the shell was consisted of poly (ethylene glycol) methyl ether methacrylate (POEGMA300). In order to compare the transition behavior of the core-shell microgels with the microgels consisted of one thermo-responsive microgel, PNIPAM and POEGMA300 microgels were prepared. PNIPAM exhibits a lower critical solution temperature (LCST) of 32 °C, and the LCST of POEGMA300 is approximately 63 °C. The thermo-responsive microgel behavior was measured by dynamic light scattering (DLS). It is observed that both of PNIPAM and POEGMA300 microgels show a thermo-responsive ability. The particle size significantly drops when the temperature passes LCST. Moreover the particle size of the thermo-responsive microgels with core (PNIPAM)-shell (POEGMA300) structure shows a linear transition behavior when the temperature is between 50 °C and 70 °C.