Spacing-dependent dipolar interactions in dendronized magnetic iron oxide nanoparticle 2D arrays and powders

Abstract

Self-assembly of nanoparticles (NPs) into tailored structures is a promising strategy for the production and design of materials with new functions. In this work, 2D arrays of iron oxide NPs with interparticle distances tuned by grafting fatty acids and dendritic molecules at the NPs surface have been obtained over large areas with high density using the Langmuir-Blodgett technique. The anchoring agent of molecules and the Janus structure of NPs are shown to be key parameters driving the deposition. Finally the influence of interparticle distance on the collective magnetic properties in powders and in monolayers is clearly demonstrated by DC and AC SQUID measurements. The blocking temperature T(B) increases as the interparticle distance decreases, which is consistent with the fact that dipolar interactions are responsible for this increase. Dipolar interactions are found to be stronger for particles assembled in thin films compared to powdered samples and may be described by using the Vogel Fulcher model.

Metal Nanoparticles with Liquid‐Crystalline Ligands: Controlling Nanoparticle Superlattice Structure and Properties

“…[75][76][77][78] Kanie et al [75] used ligand exchange reaction to prepare a series of hybrid nanoparticles with various shapes of a-Fe 2 O 3 core (with sizes of the order of hundreds of nanometers) and two mesogenic, phosphonic ligands. Few reports on Fe 2 O 3 nanoclusters covered with LC ligands were reported throughout the last few years.…”

“…Few reports on Fe 2 O 3 nanoclusters covered with LC ligands were reported throughout the last few years. [75][76][77][78] Kanie et al [75] used ligand exchange reaction to prepare a series of hybrid nanoparticles with various shapes of a-Fe 2 O 3 core (with sizes of the order of hundreds of nanometers) and two mesogenic, phosphonic ligands. Most of the obtained structures exhibited nematic ordering (one packed into cubic phase) and birefringence, up to the decomposition point above 250 8C.…”

Multifunctional Carbon Nanohorn Complexes for Cancer Treatment

“…[3] However, MAG, used alone, is unstable in physiological media and needs a coated molecular layer to improve its biocompatibility, functionality, and stability. [4][5][6] One possible way to ameliorate these physicochemical factors is by loading iron oxide nanoparticles onto functionalized nanocarbons such as carbon nanotubes (CNTs) [7][8][9][10][11] and carbon nanohorns (CNHs). [12] Because of the exceptional combination of their mechanical, electronic, and thermal properties and chemical tolerance, nanocarbons are considered unique materials, with very promising future applications in a wide range of fields.…”

Magnetic-Assembly Mechanism of Superparamagneto-Plasmonic Nanoparticles on a Charged Surface

“…The little increased T B of MPNCs can probably be attributed to the fact that the Au coating layer acts as a spacer (~ 10 nm), thereby effectively suppressing magnetic interaction between neighboring NPs. 49 In Figure 5C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 …”