Synthesis and Characterization of Temperature and pH Responsive PIA-b-PNIPAM@Fe3O4 Nanocomposites

Stimuli-responsive polymers (SRPs) have garnered significant attention in recent decades due to their immense potential in biomedical and environmental applications. When these SRPs are grafted onto magnetic nanoparticles, they form multifunctional nanocomposites capable of various complex applications, including targeted drug delivery, advanced separations, and magnetic resonance imaging. In this study, we employed a one-step hydrothermal method using 3-aminopropyltrimethoxysilane (APTES) to synthesize APTES-modified Fe3O4 nanoparticles (APTES@Fe3O4) featuring reactive terminal amine groups. Subsequently, via two consecutive surface-initiated atom transfer radical polymerizations (SI-ATRP), pH- and temperature-responsive polymer blocks were grown from the Fe3O4 surface, resulting in the formation of poly(itaconic acid)-block-poly(N-isopropyl acrylamide) (PIA-b-PNIPAM) grafted nanomagnetic particles (PIA-b-PNIPAM @Fe3O4). To confirm the chemical composition and assess how particle morphology and size distribution of these SRP-based nanocomposites change in response to ambient pH and temperature stimuli, various characterization techniques were employed, including transmission electron microscopy (TEM), differential light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). The results indicated successful synthesis, with PIA-b-PNIPAM @Fe3O4 demonstrating sensitivity to both temperature and pH.