Using small-angle scattering to guide functional magnetic nanoparticle design

in Nanoscale Advances (2022), 4

In situ magnetorheological SANS setup at Institut Laue-Langevin

in Colloid and Polymer Science (2020)

A magnetorheological sample environment is presented that allows for in situ magnetic field and shear flow during small-angle neutron scattering (SANS) measurements and is now available at the Institut ... [more ▼]

A magnetorheological sample environment is presented that allows for in situ magnetic field and shear flow during small-angle neutron scattering (SANS) measurements and is now available at the Institut Laue-Langevin (ILL). The setup allows performing simultaneous magnetorheological measurements together with the investigation of structural and magnetic changes on the nanometer length scale underlying the rheological response of ferrofluids. We describe the setup consisting of a commercial rheometer and a custom-made set of Helmholtz coils and show exemplarily data on the field and shear flow alignment of a dispersion of hematite nanospindles in water. [less ▲]

Morphological and crystallographic orientation of hematite spindles in applied magnetic field

in Nanoscale (2019), 11

Phase-Transfer and Stabilization of Highly Monodisperse Ferrite Nanoparticles into Polar Solvents by Ligand Exchange Synthesis.

in Journal of nanoscience and nanotechnology (2019), 19(8), 5048-5051

Cobalt ferrite nanoparticles with controlled particle size are transferred from nonpolar into polar solvent by exchange of the as-synthesized oleic acid ligand shell with polyacrylic acid (PAA). The ... [more ▼]

Cobalt ferrite nanoparticles with controlled particle size are transferred from nonpolar into polar solvent by exchange of the as-synthesized oleic acid ligand shell with polyacrylic acid (PAA). The nanoparticles are highly monodisperse (sigmalog < 6%), and the ligand exchange synthesis has no measurable effect on particle size, shape, or size distribution. The stability of the aqueous particle dispersion without significant interparticle correlations as observed using small-angle X-ray scattering confirms the successful phase-transfer. [less ▲]

Excitation of Ni nanorod colloids in oscillating magnetic fields: a new approach for nanosensing investigated by TISANE

in Nanoscale (2015), 7

The response of a colloidal dispersion of Ni nanorods to an oscillating magnetic field was characterized by optical transmission measurements as well as small-angle neutron scattering (SANS) experiments ... [more ▼]

The response of a colloidal dispersion of Ni nanorods to an oscillating magnetic field was characterized by optical transmission measurements as well as small-angle neutron scattering (SANS) experiments using the TISANE (Time-dependent SANS experiments) technique. Exposed to a static magnetic field, the scattering intensity of the rod ensemble could be well described by the cylinder form factor using the geometrical particle parameters (length, diameter, orientation distribution) determined by transmission electronmicroscopy and magnetometry. An oscillation of the field vector resulted in a reorientation of the nanorods and a time-dependency of the scattering intensity due to the shape anisotropy of the rods. Analysis of the SANS data revealed that in the range of low frequencies the orientation distribution of the rods is comparable to the static case. With increasing frequency, the rod oscillation was gradually damped due to an increase of the viscous drag. It could be shown that despite of the increased friction in the high frequency range no observable change of the orientation distribution of the ensemble with respect to its symmetry axis occurs. [less ▲]