Heating of polyacrylamide ferrogel by alternating magnetic field

• Published in: Journal of magnetism and magnetic materials Vol. 415; pp. 24 - 29
• Main Authors: Safronov, A.P., Samatov, O.M., Tyukova, I.S., Mikhnevich, E.A., Beketov, I.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2016
• Subjects: Adhesion; Calorimetry; Ferrofluids; Ferrogel; Heating; Iron oxide; Light scattering; Magnetic fields; Magneto-induced heating; Nanoparticles; Networks; Polymerization; Nanoparticles; Magneto-induced heating; Iron oxide; Ferrogel
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2015.11.024

Ferrogel based on polacryamide network with embedded maghemite nanoparticles with mean number average particle diameter 12nm was synthesized by radical polymerization in water-based ferrofluid. The network structure of ferrogel was characterized by Flory–Rehner theory and it was shown that the embedded particles were substantially larger than the mesh size. It prevented the translational movement of particles in the ferrogel. The immobilization of particles was confirmed by dynamic light scattering. The adhesion of macromolecular chains to the particles was determined by calorimetry using thermochemical cycle. The enthalpy of interfacial adhesion was found several orders of magnitude higher than the energy of dipoles in typically applied magnetic fields. Despite the differenve in the mobility of particles in ferrofluid and ferrogel the comparative study of their heating in alternating magnetic field, however, revealed their close similarity. In both cases it was goverened by superposing of Neel and Brownian relaxation mechanisms. •We synthesized polyacrylamide ferrogel with maghemite nanoparticles.•Nanoparticles are entrapped into gel network.•Polyacrylamide chains are strongly linked to the particles.•Brownian relaxation contributes to heating of ferrogel in alternating field.