Rheological investigation of magnetic sensitive biopolymer composites: effect of the ligand grafting of magnetic nanoparticles

Abstract

This study investigated the steady shear flow and viscoelastic properties of composite materials elaborated by introduction of positively charged polyol-made maghemite nanoparticles (NPs) in aqueous solutions of negatively charged sodium alginate polymers. Two different ligands were covalently attached to the particle surface, the 3-aminopropyl triethyloxysilane (APTES) and the 3,4-dihydroxyphenylethylamine (DOPA), and their effect on the general rheological and magneto-rheological behaviors of the resulting composites was highlighted. Indeed, the experiments revealed that the increase of low shear viscosity and the viscoelastic moduli in the linear viscoelastic domain can be correlated to the nature of the two ligands inducing either compact or loose aggregates between positively charged NPs and negatively charged biopolymer chains. These field-induced microstructures have been qualitatively observed by optical microscopy under applied magnetic field.

Magnetic Nanoparticles for Biomedical Purposes: Modern Trends and Prospects

“…The average particle size, depending on the polyol used, varies from 7 to 15 nm [34]. Roughly spherical, highly crystallized, and almost uniform in size, maghemite nanoparticles of average size 11 nm are synthesized by forced hydrolysis of iron acetates in a diethylene glycol [35,36].…”

Effect of the surface coating of carbonyl iron particles on the dispersion stability of magnetorheological fluid

“…After being etched, the density of the particles decreased from 7.729 to 7.604 g/cm 3 , due to the formation of numerous porous structures on the www.nature.com/scientificreports/ particle surfaces, the etching slightly changed the particle density. When BTES was coated, the density of the single-layer coated particles (HCIP-BTES) decreased to 6.289 g/cm 3 , the density of double-layer coated particles (HCIP-BTES-TOS) decreased to 5.298 g/cm 3 , and the density of double-layer coated particles with longer carbon chains (HCIP-BTES-DTOS) further decreased to 5.036 g/cm 3 . This suggests that HCl etching, single-layer or double-layer coating, and silane coupling agent chain length can further affect the particle density.…”

“…Magnetorheological fluids (MRFs) are primarily composed of magnetic particles, a carrier medium, and additives. Without a magnetic field, the magnetic particles are randomly distributed in the carrier medium, and the MRF is a free-flowing Newtonian fluid; under a magnetic field, chain structures of the magnetic particles form along the direction of the magnetic field within milliseconds, the solid-like Bingham plastic material property of the MRF appears, and the wide variation range of the yield stress is between 20 and 100 kPa 1 – 3 . As an intelligent controllable material, MRF is widely used in damping, transmission devices, sealing, polishing, and medical equipment, etc., owing to its unique magnetorheological effect 4 – 8 .…”

Magnetorheological properties of Fe–Co nanoparticles with high saturation magnetization and low coercivity

“…In comparison to the others particles, Fe-Co particles can assemble into stronger chain-like structure because of their high saturation magnetization, which are beneficial to improve the MR properties of MRFs [15]. Furthermore, sedimentation stability is also a critical indicator to measure MRFs performance, the recent studies have manifested that nanoparticles possess excellent sedimentation stability because of a low particle density and size [16]. However, the MR properties inevitably tends to decrease with the reduction of magnetic particles size [17].…”