Structural and magnetic behavior of ferrogels obtained by freezing thawing of polyvinyl alcohol/poly(acrylic acid) (PAA)-coated iron oxide nanoparticles

• Published in: European polymer journal Vol. 49; no. 2; pp. 279 - 289
• Main Authors: Moscoso-Londoño, O., Gonzalez, J.S., Muraca, D., Hoppe, C.E., Alvarez, V.A., López-Quintela, A., Socolovsky, L.M., Pirota, K.R.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-02-2013; Elsevier
• Subjects: Applied sciences; Composites; Exact sciences and technology; Ferrogel; Forms of application and semi-finished materials; Iron oxides; Magnetic nanoparticles; Magnetic properties; Polymer industry, paints, wood; Technology of polymers; Ferrogel; Iron oxides; Magnetic nanoparticles; Magnetic properties; Iron oxide; Dispersion degree; Gelation; Temperature effect; Physical gel; Superparamagnetism; Crystallinity; Experimental study; Composite particles; Freeze thaw cycle; Polyvinylalcohol; Magnetic material; Morphology; Acrylic acid polymer; Coercive force; Nanocomposite; Manufacturing; Hydrogel; Growth from solution
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2012.11.007

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► Ferrogels were obtained by freezing thawing of PVA/PAA-coated magnetic NPs. ► Strong H-bonding between PAA–PVA allowed homogeneous dispersion of NPs in the matrix. ► Polyelectrolyte nature of the coating increased swelling of the ferrogels. ► Magnetic and physical properties make these gels promising for biomedical applications.
Superparamagnetic ferrogels with high swelling ability and potential applications as solvent absorbers and stimuli-responsive drug delivery devices were obtained by a non-toxic and environmentally friendly route based on dispersion of poly(acrylic acid)-coated iron oxide nanoparticles (PAA-coated NPs) in poly(vinyl alcohol) (PVA) solutions followed by freezing–thawing. Presence of carboxylate groups arising from the PAA coating allowed hydrogen bonding formation between NPs and PVA and enabled the synthesis of optically homogenous, superparamagnetic materials formed by a homogenous distribution of NPs diffuse clusters in the PVA matrix. The addition of PAA-coated NPs produced a remarkable increase in crystallinity degree, thermal degradation and swelling percentage respect to the neat matrix, which demonstrates that ferrogels with improved properties can be obtained by this procedure. Thereafter, combination of a cryogenic technique with the use of non-toxic components and magnetic NPs coated by a pH sensitive polymer makes these ferrogels very promising for applications in the biomedical field.