Azide-terminated magnetic iron oxide nanoparticles have been assembled in 2D on alkyne-terminated self-assembled monolayers (SAMs) by the copper(i) catalyzed alkyne-azide cycloaddition (CuAAC) "click" reaction; the kinetics of the reaction is an important parameter to control the interparticle distance and thus the dipolar interactions.
1D assemblies of magnetic nanoparticles are of great potential for designing novel nanostructured materials with enhanced collective magnetic properties. In that challenging context, a new assembly strategy is presented to prepare chains of magnetic nanoparticles that are well‐defined in structure and in spatial arrangement. The 1D assembly of iron oxide nanoparticles onto a substrate is controlled using “click” chemistry under an external magnetic field. Co‐aligned single nanoparticle chains separated by regular distances can be obtained by this strategy. The intrinsic high uniaxial anisotropy results in a strong enhancement of magnetic collective properties in comparison to 2D monolayers or isolated nanoparticles. In contrast to the intensively studied bundle chains of nanoparticles, the finely tuned chain structure reported here allows evidencing a first order intrachain dipolar interaction and a second order interchain magnetic coupling. This study offers new insights into the collective magnetic properties of highly anisotropic particulate assemblies which have been investigated by combining superconducting quantum interference device magnetometry, magnetic force microscopy, and ferromagnetic resonance.
Two dimensional (2D) nanoparticles (NP) assemblies have become very attractive due to their original collective properties, which can be modulated as a function of the nanostructure. Beyond precise control on nanostructure and easy way to perform, fast assembling processes are highly desirable to develop efficient and popular strategies to prepare systems with tunable collective properties. In this article, we report on the highly efficient and fast 2D assembling of iron oxide nanoparticles on a self-assembled monolayer (SAM) of organic molecules by the microwave (MW)-assisted copper(I) catalyzed alkyne−azide cycloaddition (CuAAC) click reaction. Microwave irradiation favors a dramatic enhancement of the assembling reaction, which was completed with maximum density in NPs within one hour, much faster than the conventional CuAAC click reactions that require up to 48 h. Moreover, the MWassisted click reaction presents the great advantage to preserve specific reactions between alkyne and azide groups at SAM and NP surfaces, respectively, and also to avoid undesired reactions. To the best of our knowledge, this is the first time this approach is performed to nanoparticles assembled on surfaces.
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