Ferro-Self-Assembly: Magnetic and Electrochemical Adaptation of a Multiresponsive Zwitterionic Metalloamphiphile Showing a Shape-Hysteresis Effect

10.26434/chemrxiv.12370406.v1 ◽

2020 ◽

Author(s):

Stefan Bitter ◽

Moritz Schlötter ◽

Markus Schilling ◽

Rainer Winter ◽

Sebastian Polarz

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Self Assembly ◽

Hysteresis Effect ◽

The Self ◽

Stimuli Responsive ◽

Tubular Aggregates ◽

Optical Birefringence ◽

Sufficient Concentration

We report on a novel multi-stimuli-responsive amphiphile, 1-(Z)-heptenyl-1’-dimethylammonium-methyl-(3-sulfopropyl)ferrocene (6), whose self-assembly properties can be altered by three different stimuli, namely: (i) the addition of external salts which serve to unfold the sultone headgroup, thus triggering self-assembly of 6 into vesicles; (ii) oxidation to 6+, which changes the lipophilic ferrocene to a hydrophilic ferrocenium entity, thereby broadening the size-distribution of the aggregates; and (iii) exposition of 6+ to an external magnetic field of 0.8 T. Under thease conditions and at sufficient concentration, 6+ forms large, tubular aggregates with lengths of up to 15 µm, which persist for over 5 min after the field is switched off again. 6+ is thus the first amphiphile to exhibit a shape-hysteresis effect. The self-assembly/disassembly processes and their dynamics were studied live and in situ by optical birefringence measurements coupled to light scattering.

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Ferro-self-assembly: magnetic and electrochemical adaptation of a multiresponsive zwitterionic metalloamphiphile showing a shape-hysteresis effect

Chemical Science ◽

10.1039/d0sc05249c ◽

2021 ◽

Vol 12 (1) ◽

pp. 270-281

Author(s):

Stefan Bitter ◽

Moritz Schlötter ◽

Markus Schilling ◽

Marina Krumova ◽

Sebastian Polarz ◽

...

Keyword(s):

Magnetic Field ◽

Light Scattering ◽

Dynamic Light Scattering ◽

Real Time ◽

Self Assembly ◽

Hysteresis Effect ◽

The Self ◽

Self Organization ◽

Stimuli Responsive ◽

Optical Birefringence

The self-organization properties of a stimuli responsive amphiphile can be altered by subjecting the paramagnetic oxidized form to a magnetic field of 0.8 T and monitored in real time by coupling optical birefringence with dynamic light scattering.

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Self-assembly of smallest magnetic particles

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1511443112 ◽

2015 ◽

Vol 112 (47) ◽

pp. 14484-14489 ◽

Cited By ~ 44

Author(s):

Sara Mehdizadeh Taheri ◽

Maria Michaelis ◽

Thomas Friedrich ◽

Beate Förster ◽

Markus Drechsler ◽

...

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Data Storage ◽

Self Assembly ◽

Magnetic Particles ◽

Dipole Interaction ◽

The Self ◽

Magnetic Structures ◽

Medical Technologies ◽

1D Chains

The assembly of tiny magnetic particles in external magnetic fields is important for many applications ranging from data storage to medical technologies. The development of ever smaller magnetic structures is restricted by a size limit, where the particles are just barely magnetic. For such particles we report the discovery of a kind of solution assembly hitherto unobserved, to our knowledge. The fact that the assembly occurs in solution is very relevant for applications, where magnetic nanoparticles are either solution-processed or are used in liquid biological environments. Induced by an external magnetic field, nanocubes spontaneously assemble into 1D chains, 2D monolayer sheets, and large 3D cuboids with almost perfect internal ordering. The self-assembly of the nanocubes can be elucidated considering the dipole–dipole interaction of small superparamagnetic particles. Complex 3D geometrical arrangements of the nanodipoles are obtained under the assumption that the orientation of magnetization is freely adjustable within the superlattice and tends to minimize the binding energy. On that basis the magnetic moment of the cuboids can be explained.

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Self-assembly mechanism of Ni nanowires prepared with an external magnetic field

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.6.217 ◽

2015 ◽

Vol 6 ◽

pp. 2123-2128 ◽

Cited By ~ 12

Author(s):

Xiaoyu Li ◽

Hu Wang ◽

Kenan Xie ◽

Qin Long ◽

Xuefei Lai ◽

...

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Self Assembly ◽

Chemical Reduction ◽

Reaction System ◽

The Self ◽

Nickel Nanowires ◽

Assembly Mechanism ◽

Nickel Particles ◽

First Time

Nickel nanowires with a mean diameter of about 95 nm and lengths of up to 26 μm were prepared by a chemical reduction method in aqueous solution under an external magnetic field. The self-assembly mechanism was investigated in detail. The results indicate that the self-assembly process of Ni nanowires consists of three stages: nucleation and growth, ordered alignment and self-assembly, and deposition on the surface and gaps between the nickel particles. The self-assembly phenomenon occurs only when nickel particles grow to a size of about 60 nm in the reaction system. This critical size, which is proposed for the first time, is very important to comprehend the self-assembly mechanism of Ni nanowires prepared with an external magnetic field.

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