Synthesis of a thermoresponsive crosslinked MEO2MA polymer coating on microclusters of iron oxide nanoparticles
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Lapresta-Fernández, A., Salinas-Castillo, A., & Capitán-Vallvey, L. F. (2021). Synthesis of a thermoresponsive crosslinked MEO 2 MA polymer coating on microclusters of iron oxide nanoparticles. Scientific reports, 11(1), 1-8. [
SponsorshipAndalusian Knowledge Agency; European Commission 291780; Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía; Spanish "Ministerio de Economía y Competitividad" PID2019-103938RB-I00 CTQ2017-86125-P; Junta de Andalucía B-FQM-243-UGR18 P18-RT-2961; CEI-Biotic CEI2013-MP-10
Encapsulation of magnetic nanoparticles (MNPs) of iron (II, III) oxide ( Fe3O4) with a thermopolymeric shell of a crosslinked poly(2-(2-methoxyethoxy)ethyl methacrylate) P(MEO2MA) is successfully developed. Magnetic aggregates of large size, around 150–200 nm are obtained during the functionalization of the iron oxide NPs with vinyl groups by using 3-butenoic acid in the presence of a water soluble azo-initiator and a surfactant, at 70 °C. These polymerizable groups provide a covalent attachment of the P(MEO2MA) shell on the surface of the MNPs while a crosslinked network is achieved by including tetraethylene glycol dimethacrylate in the precipitation polymerization synthesis. Temperature control is used to modulate the swelling-to-collapse transition volume until a maximum of around 21:1 ratio between the expanded: shrunk states (from 364 to 144 nm in diameter) between 9 and 49 °C. The hybrid Fe3O4@ P(MEO2MA) microgel exhibits a lower critical solution temperature of 21.9 °C below the corresponding value for P(MEO2MA) (bulk, 26 °C). The MEO2MA coating performance in the hybrid microgel is characterized by dynamic light scattering and transmission electron microscopy. The content of preformed MNPs [up to 30.2 (wt%) vs. microgel] was established by thermogravimetric analysis while magnetic properties by vibrating sample magnetometry.