Colloidal Polymers with Controlled Sequence and Branching Constructed from Magnetic Field Assembled Nanoparticles

Abstract

The assembly of nanoparticles into polymer-like architectures is challenging and usually requires highly defined colloidal building blocks. Here, we show that the broad size-distribution of a simple dispersion of magnetic nanocolloids can be exploited to obtain various polymer-like architectures. The particles are assembled under an external magnetic field and permanently linked by thermal sintering. The remarkable variety of polymer-analogue architectures that arises from this simple process ranges from statistical and block copolymer-like sequencing to branched chains and networks. This library of architectures can be realized by controlling the sequencing of the particles and the junction points via a size-dependent self-assembly of the single building blocks.

Bioinspired 1D Superparamagnetic Magnetite Arrays with Magnetic Field Perception

“…Generally, these magnetite nanoparticles can be fabricated into ordered assembles by applying a magnetic field, yielding ordered alignment of nanoparticles along the magnetic field. [16,17] However, these assembled nanoparticles have limited magnetization anisotropy due to the low aspect ratio of the prepared micro-/nanostructure arrays, especially the 1D arrays. To improve the anisotropy, some micro-/ nanoprocessing methods, such as light/electron-beam lithography, [18] focused ion beam lithography [19] and templating techniques, [20] can be employed to assemble nanoparticles into high-aspect-ratio patterns with designable geometric parameters.…”

Recent Advances in Multicomponent Particle Assembly

“…The particles can be assembled and subsequently fused in the presenceo fa ne xternal magnetic field, and various architectures with polymer resemblancec an be achieved. [70] Binary mixtures of polarizable particles confined to am onolayer can assemble into av ariety of crystal structuresd riven by antiferromagnetic interaction (Figure 3c). By controlling the relative concentrations and interaction strength between paramagnetic and non-magnetic particles, kagome, honeycomb, squarel attices, and variousc hain and ring structuresc an be programmed.…”

Flexible Ferrofluids: Design and Applications

“…Based on the significant progress in both theoretical and technical aspects, a large number of breakthroughs have been reported and the application fields of ferrofluids have been largely expanded. Apart from employing them widely in energy and mechanical engineering areas, researchers also associate ferrofluids with novel optical or polymerizable materials and thus develop multiple kinds of composite materials such as polymer‐like architectures, magnetically responsive photonic crystals, and microrobots . Besides, when integrated into microfluidic systems, ferrofluids are found to achieve a broad range of applications from droplet manipulation to on‐demand synthesis and detection .…”

“…Apart from employing them widely in energy and mechanical engineering areas, [23,24] researchers also associate ferrofluids with novel optical or polymerizable materials and thus develop multiple kinds of composite materials such as polymer-like architectures, magnetically responsive photonic crystals, and microrobots. [25][26][27] Besides, when integrated into microfluidic systems, ferrofluids are found to achieve a broad range of applications from droplet manipulation to on-demand synthesis and detection. [28] More importantly, the function of ferrofluids in biomedical areas is highlighted as they facilitate diagnosis and therapy of diseases such as cancer, angiocardiopathy, and rheumatoid arthritis.…”