Smart shape-controlled synthesis of poly(N-isopropylacrylamide)/chitosan/Fe3O4 microgels

A novel approach was developed to synthesize smart shape-controlled PNIPAM/CS/Fe3O4 microgels with uniform size. Interestingly, the microgels in spindle-shaped, cuboid and spherical morphologies were successfully prepared using the micro-emulsion polymerization at a low temperature from 28 to 40 degrees C based on the theory of coil-to-globule. The morphology and properties of the as-prepared products were investigated using scanning electron microscope (SEM), dynamic light scattering (DLS) and superconducting quantum interference device (SQUID). Results revealed that the PNIPAM/CS/Fe3O4 microgels exhibited good thermo- and pH-sensitivities, and the size of the microgels decreased sharply upon increasing the temperature around 32 degrees C. The microgels with various shapes show a great promise in bioseparation and many other fields in the future. (C) 2015 Elsevier Ltd. All rights reserved.