Polyacrylic acid-coated iron oxide magnetic nanoparticles: The polymer molecular weight influence

Abstract

Magnetic nanoparticles (MNPs), in particular, magnetic iron oxide-based nanoparticles were found to be useful as catalysts and as devices for data storage, environmental remediation and several biomedical applications, due to their excellent properties, such as biocompatibility and high magnetic moment. Polyacrylic acid (PAA) is a weak polyelectrolyte that can be used to stabilize the MNPs. To the best of our knowledge, the influence of PAA molecular weight and PAA concentration over the magnetic and structural properties of iron oxide nanoparticles has not been previously reported. The aim of this paper is to describe the differences evidenced in the properties of different magnetic materials by using PAA for iron oxides stabilization by onepot coprecipitation synthesis. Iron oxide-based magnetic nanoparticles stabilized by polyacrylic acid (PAA) polymers were efficiently prepared and exhaustively characterized. The influence on the employment of two different low PAA molecular weights, Mw 1800 g/mol and 5000 g/mol, in three different iron salts: PAA ratios was analyzed. In summary, the main results showed that: for a certain PAA reactor feed higher oligomer quantities are present in MNPs as higher is the involved molecular weight of the polymeric chain; when molecular weight raises the contribution of loops and tails also does it, allowing having higher polymer contents. For both PAA's Mw employed as the adsorbed PAA increases particles hydrodynamic diameters decreases, and their distribution becomes narrower; the PAA adsorbs onto iron oxides by chemisorption (the most probable interaction is the bidentate bridging). For the studied cases z potential values depend much more on the PAA's quantity adsorbed onto the iron oxides than on the PAA's Mw. MNPs are superparamagnetic and choosing the right shape of particle distribution is not central for getting estimates of the magnetization saturation, the average particle diameter and its standard deviation, while better fits are found with Normal and Log-Normal particle size distributions.

A facile one-pot synthesis of poly(acrylic acid)-functionalized magnetic iron oxide nanoparticles for suppressing reactive oxygen species generation and adsorption of biocatalyst

“…Further, the intensity of diffraction signals remains almost identical after surface modification. In addition,a broad reflection also observed at 2θ region of 17 to 24°i n the XRD profile of PAA1 functionalized IONPs due to the presence of amorphous PAA on the surface of the particles that demonstrates the successful functionalization of the nanocomposite particles [41,42]. However, in figure 4(c) for PAA3-functionalized IONPs, some intense peaks for IONPs have become weak which might be due to the surface coverage of IONPs with PAA3.…”

“…Dextran-coated IONPs were functionalized with a cell penetrating peptide and used to inhibit the excessive formation of ROS for the treatment of lung cancer [21]. In recent years, several possible functionalizing agents, such as poly(acrylic-co-maleic), poly(trolox ester) polymers, natural antioxidants (quercetin, curcumin,green tea polyphenols, and anthocyanins),ascorbic, citric, humic, gallic, and polyacrylic acids have also been used to functionalize the bare surface of IONPs to improve colloidal stability and surface properties [20][21][22][23]. Among these surface functionalizing agents, poly(acrylic acid) (PAA) provides both electrostatic and steric repulsions against particles to stabilize their dispersion via surface functionalization of bare IONPs [24].…”

Inhibitive effect of super paramagnetic iron oxide nanoparticles on the alkaline hydrolysis of procaine

“…The SPIONs give the freedom to control the morphology, shape and size of the nanoparticles during the synthesis process, which can be used further in different applications [10][11][12][13]. The surface of iron oxide nanoparticles can be modified or coated as per need using various polymers, surfactants and inorganic materials like silica [14][15][16][17][18]. These nanocatalysts have successfully been used for catalysing the organic reactions like carbon-carbon coupling reactions, oxidations, epoxidation reactions and hydro-formylation reactions.…”

Applications of magnetic materials separation in biological nanomedicine

“…Biocompatible polymers used to modify MBs can be classified into the two categories: (i) natural macromolecules (such as glucan, chitosan, and amino acids); (ii) synthetic macromolecules (such as PEG, PVP, PS, PMMA, and PLA). At present, the research on organic polymer modified MBs mainly focuses on the two aspects: (i) the synthesis of polymer MBs with high content and uniform size; (ii) the development of polymer/MBs composite particles with a clear core‐shell structure . Notable efforts concerning these research directions are discussed in the following paragraphs.…”