Spontaneous in-flight assembly of magnetic nanoparticles into macroscopic chains

Abstract

The cluster gun technique can go beyond fabrication of single particles into controlled and reproducible self-assembly of NPs as they form.

Finding the Limits of Magnetic Hyperthermia on Core-Shell Nanoparticles Fabricated by Physical Vapor Methods

“…The shell thickness is around 3 nm. Another important characteristic of nanocuboids is their broader tendency to self-assemble into long-range mesoscopic chains, with the presence of the flat surface facilitating the stability of such an arrangement in comparison to the spherical particles [8]. Such an effect, which is enhanced upon the drying of the dispersion, explains the higher aggregation rate of cubic nanoparticles giving the impression of a larger concentration in TEM images (Figure 2b).…”

“…Therefore, it seems that improvement of the K eff term is a dominant SLP-defining parameter overcoming the role of the contribution of the higher M S observed for the spherical counterparts. Furthermore, the assembling of the nanocubes in a chainlike fashion increases the correlation length, thus modifying the response to external stimuli [8,10,54]. This effect stems from the dependence of the entropy and dipolar interactions on the length of the chain, although the particular details will depend also on the chain orientation with respect to the field direction [52].…”

“…diameter DC magnetron cluster source operating at 30 W in the low 10 −3 Torr range. Deposition took place at a production rate of 1 mg/h using a (Fe 99.95%) target-to-substrate (corning glass) distance of 25 cm with Ar flow regulated at around 80 cm 3 /min in a modification of the process reported previously [8,63]. It is envisaged that given the effective high temperature near the target surface, the crystallinity could also be increased, resulting in a cubic shape vs. the lower temperature synthesis of spherical NPs by SPVD.…”

Fine tuning and optimization of magnetic hyperthermia treatments using versatile trapezoidal driving-field waveforms

“…Considering nanoparticles as non-interacting is of course an approximation, and in some cases it may be an over-simplication. [47][48][49][50][51][52] The assumption is however reasonable in the light of the ultimate aim of the paper, which is to highlight the advantages of applying a non-conventional driving eld waveform on the SLP of a set of dispersed nanoparticles, independent of their degree of interaction. It should be noted that in the current therapeutic practice there is a tendency towards the reduction of the concentration of inoculated magnetic particles (associated with optimization of their SLP), 11 in order to minimize potentially negative effects on the patient's body.…”

Assembly of nanocube super-structures directed by surface and magnetic interactions

“…19 (D) Self-assembled chain in gas phase of 25 nm iron/iron-oxide core/shell magnetic nanocubes, adapted with permission from ref. 17 (E) SEM image of a 3D cuboid which consists of more than 10,000 iron-oxide nanocubes. Adapted with permission from ref.…”