Fine-Tuning the Degree of Negative Charge and Carboxylate Grafting Density of Polymer-Coated Magnetite Nanoparticle

The surface of magnetite nanoparticle (MNP) was modified with poly(acrylic acid)(PAA)-poly(ethylene glycol) methyl methacrylate (PEGMA) (co)polymer to obtain water dispersible MNP pH sensitive surfaces via atom transfer radical polymerization (ATRP) tert-butyl acrylate (t-BA), followed by the t-BA group deprotection. Molar compositions were systematically varied, namely 100:0, 75:25, 50:50 and 25:75 P(t-BA)/PEGMA, respectively, such that grafting density carboxylate groups on after deprotection can be fine-tuned. Transmission electron microscopy (TEM) indicated spherical (ca.5-12 nm in diameter) some nanoclustering observed. roles PAA PEGMA affecting hydrodynamic size zeta potential nanocomposites observed photocorrelation spectroscopy (PCS) discussed. percentages polymeric composition each step reaction determined thermogravimetric analysis (TGA) their magnetic properties studied vibrating sample magnetometry (VSM). These novel magnetically guidable might advantageous for further conjugations either covalent or ionic bonding bioentities. HIGHLIGHTS Magnetite coated fabricated ATRP ratio used copolymerization showed GRAPHICAL ABSTRACT