Preparation of P(NIPAM-co-AA) Microcontainers Surface-Anchored with Magnetic Nanoparticles

P(NIPAM-co-AA) microcontainers surface-anchored with magnetic nanoparticles were prepared using PSt/P (NIPAM-co-AA) core/shell microspheres and amino-modified Fe3O4@SiO2 particles as building blocks. At first, the PSt/P(NIPAM-co-AA) core/shell microspheres were prepared by seeded emulsion polymerization, and the amino-modified Fe3O4@SiO2 particles were prepared by a modified Stober method followed by functionalized by 3-aminopropyltriethoxysilane. Then, the smaller amino-modified Fe3O4@SiO2 particles were assembled onto the surface of PSt/P(NIPAM-co-AA) core/shell microspheres by electrostatic interaction. Subsequently, the two particles were permanently combined through amidation reaction between carboxylic groups and amino groups under the catalysis of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. By dissolving the PSt core with tetrahydrofuran, novel triple-functional microcontainers with superparamagnetism and pH and temperature sensitivity were obtained.