Surface‐Initiated Atom Transfer Radical Polymerization of Magnetite Nanoparticles with Statistical Poly(tert‐butyl acrylate)‐poly(poly(ethylene glycol) methyl ether methacrylate) Copolymers

Abstract

This work presented the surface modification of magnetite nanoparticle (MNP) with poly[(t-butyl acrylate)-stat-(poly(ethylene glycol) methyl ether methacrylate)] copolymers (P[(t-BA)-stat-PEGMA])viaa surface-initiated “grafting from” atom transfer radical polymerization (ATRP). Loading molar ratio oft-BA to PEGMA was systematically varied (100 : 0, 75 : 25, 50 : 50, and 25 : 75, resp.) such that the degree of hydrophilicity of the copolymers, affecting the particle dispersibility in water, can be fine-tuned. The reaction progress in each step of the synthesis was monitoredviaFourier transform infrared spectroscopy (FTIR). The studies in the reaction kinetics indicated that PEGMA had higher reactivity than that oft-BA in the copolymerizations. Gel permeation chromatography (GPC) indicated that the molecular weights of the copolymers increased with the increase of the monomer conversion. Transmission electron microscopy (TEM) revealed that the particles were spherical with averaged size of 8.1 nm in diameter. Dispersibility of the particles in water was apparently improved when the copolymers were coated as compared to P(t-BA) homopolymer coating. The percentages of MNP and the copolymer in the composites were determinedviathermogravimetric analysis (TGA) and their magnetic properties were investigatedviavibrating sample magnetometry (VSM).

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

“…Fe(acac)3 (0.5 g, 1.41 mmol) was dissolved in benzyl alcohol (90 mL) and magnetically stirred at 180 °C for 48 h with nitrogen flow [26]. The particle was magnetically separated, washed with ethanol and CH2Cl2 and then dried in vacuo.…”

“…For example, it can be used to separate specific proteins via ion exchange and to covalently bind a variety of biomolecules [22,24,25]. In this work, the surface-initiated ATRP of P(t-BA)/PEGMA (co)polymer mediated by a copper complex was first carried out and the detail of this part has been previously reported [26]. The t-butyl groups on the particle surface were then deprotected to obtain the carboxylate groups on its surface [27,28].…”

Numerical Simulation of Atom-Transfer Radical Polymerization of tert-butyl Methacrylate

“…Block copolymers based on tert-butyl methacrylate (tBMA) have many uses, such as in its incorporation in thermo-responsive polymers with a lower critical solution temperature 25 , peptide-polymer conjugates with selforganizing property and biological activities 26 , well-defined amphiphilic graft copolymers 27 , polymers with very good electrochemical 28 and magnetic performances 29 , and also many applications in the medical field [30][31][32][33] . This recent application growth of tBMA-based materials suggests a need for in-depth knowledge of synthesis by ATRP.…”