Superparamagnetic iron oxide (Fe3O4) nanoparticles were modified with a pH and temperature responsive block copolymer, poly(itaconic acid)-block-poly(N-isopropylacrylamide) (PIA-b-PNIPAM), via aqueous surface-initiated atom transfer radical polymerization (SI-ATRP). Neat and modified magnetic nanoparticles (MNPs) were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) to discern morphology and chemical composition. Dynamic light scattering (DLS) and thermogravimetric analysis (TGA) were used to obtain the particle size distribution and phase transitions in response to temperature, and the grafting percentage, respectively. The Fe3O4-PIA-b-PNIPAM nanocomposites have a magnetic core surrounded by a 'shell' comprised of a block copolymer with amphiphilic stimuli-responsive blocks. The chemical composition and morphology of these MNPs modified with PIA-b-PNIPAM was confirmed, and the thermoresponsiveness of the size of these nanocomposites was demonstrated. (C) 2014 Published by Elsevier B.V.