Structuralization of magnetic nanoparticles in 5CB liquid crystals

Gdovinová, Veronika; Schroer, Martin A.; Tomašovičová, Natália; Appel, Ingo; Behrens, Silke; Majorošová, Jozefína; Kováč, J.; Svergun, Dmitri I.; Kopčanský, P.

doi:10.1039/c7sm01234a

Cited by 26 publications

(19 citation statements)

References 35 publications

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“…All observations discussed apparently suggest the existence of different types of the magnetic exchange interaction in the colloids under the variation of MNPs concentration. We suppose that the driving mechanism responsible for such unexpected behavior could be found in the formation of different magnetic clusters in CFO-LC at the specific concentration of MNPs ( Demortiére et al., 2010 ; Gdovinová et al., 2017 ). As shown by Clime and Veres ( 2007 ), the magnetization of densely packed interacting superparamagnetic nanoparticles assembled into clusters can increase or decrease compared with non-interacting particles, depending on the size and dimensionality of clusters.…”

Section: Resultsmentioning

confidence: 94%

“…The choice of this specific MNP was motivated by its wide range of interesting properties like the high chemical stability, mechanical hardness, high coercivity, moderate saturation magnetization, and large magneto-crystalline anisotropy ( Hashim et al., 2012 ; Sanpo et al., 2013 ; Momin et al., 2015 ; Sharifi et al., 2012 ; Hähsler et al., 2020 ; Zákutná et al., 2020 ), which allow us to expect an unconventional macroscopic behavior of MNP-doped LCs. Indeed, the obtained results in Gdovinová et al. (2017 ) showed a rapid change in magnetization for a concentrated FN sample contrary to its diluted counterpart in which the influence of MNPs is negligible in comparison with the undoped LC.…”

Section: Introductionmentioning

confidence: 87%

“…Therefore, various surfactants are extensively studied for coating the MNP's surface to decrease or avoid aggregation of MNPs and improve the long-time stability ( Podoliak et al., 2012 ). Recent studies have elaborated specific surface engineering of MNPs with (pro-) mesogenic ligands to prepare NP-LC hybrids and tuning their compatibility with thermotropic LC hosts ( Demortiére et al., 2010 ; Appel et al., 2017 ; Gdovinová et al., 2017 ; Hähsler et al., 2021 ). The stability of colloids crucially determines the structure-property relationships and future applications.…”

Section: Introductionmentioning

confidence: 99%

“…The stability of colloids crucially determines the structure-property relationships and future applications. In our previous work we have studied the changes in the LC structure of a simple nematic mesogen caused by doping with mesogen-hybridized CoFe 2 O 4 -MNPs as well as the influence of phase transition on the colloidal stability, especially on the alignment of MNPs ( Gdovinová et al., 2017 ). The choice of this specific MNP was motivated by its wide range of interesting properties like the high chemical stability, mechanical hardness, high coercivity, moderate saturation magnetization, and large magneto-crystalline anisotropy ( Hashim et al., 2012 ; Sanpo et al., 2013 ; Momin et al., 2015 ; Sharifi et al., 2012 ; Hähsler et al., 2020 ; Zákutná et al., 2020 ), which allow us to expect an unconventional macroscopic behavior of MNP-doped LCs.…”

Section: Introductionmentioning

confidence: 99%

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Clustering in ferronematics—The effect of magnetic collective ordering

et al. 2021

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Summary Clustering of magnetic nanoparticles can dramatically change their collective magnetic properties, and it consequently may influence their performance in biomedical and technological applications. Owing to tailored surface modification of magnetic particles such composites represent stable systems. Here, we report ferronematic mixtures that contain anisotropic clusters of mesogen-hybridized cobalt ferrite nanoparticles dispersed in liquid crystal host studied by different experimental methods—magnetization measurements, small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS), and capacitance measurements. These measurements reveal non-monotonic dependencies of magnetization curves and the Fréedericksz transition on the magnetic nanoparticles concentration. This can be explained by the formation of clusters, whose structures were determined by SAXS measurements. Complementary to the magnetization measurements, SANS measurements of the samples were performed for different magnetic field strengths to obtain information on the orientation of the liquid crystal molecules. We demonstrated that such hybrid materials offer new avenues for tunable materials.

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Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Clustering in ferronematics—The effect of magnetic collective ordering

et al. 2021

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“…Ten reconstructions, starting with random configurations, were performed and the resultant models were superimposed and analyzed. While the ab initio modelling approach is routinely used for biological SAXS, it has also, more recently, been applied to data from nanoparticles [ 44 , 45 , 46 ] and biological–nanoparticle hybrid systems [ 23 ].…”

Section: Methodsmentioning

confidence: 99%

Dependence of the Nanoscale Composite Morphology of Fe3O4 Nanoparticle-Infused Lysozyme Amyloid Fibrils on Timing of Infusion: A Combined SAXS and AFM Study

Schroer

Tomašovičová

et al. 2021

Molecules

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Understanding the formation process and the spatial distribution of nanoparticle (NP) clusters on amyloid fibrils is an essential step for the development of NP-based methods to inhibit aggregation of amyloidal proteins or reverse the assembling trend of the proto-fibrillary complexes that prompts pathogenesis of neuro degeneration. For this, a detailed structural determination of the diverse hybrid assemblies that are forming is needed, which can be achieved by advanced X-ray scattering techniques. Using a combined solution small angle X-ray scattering (SAXS) and atomic force microscopy (AFM) approach, this study investigates the intrinsic trends of the interaction between lysozyme amyloid fibrils (LAFs) and Fe3O4 NPs before and after fibrillization at nanometer resolution. AFM images reveal that the number of NP clusters interacting with the lysozyme fibers does not increase significantly with NP volume concentration, suggesting a saturation in NP aggregation on the fibrillary surface. The data indicate that the number of non-adsorbed Fe3O4 NPs is highly dependent on the timing of NP infusion within the synthesis process. SAXS data yield access to the spatial distribution, aggregation manner and density of NP clusters on the fibrillary surfaces. Employing modern data analysis approaches, the shape and internal structural morphology of the so formed nanocomposites are revealed. The combined experimental approach suggests that while Fe3O4 NPs infusion does not prevent the fibril-formation, the variation of NP concentration and size at different stages of the fibrillization process can impose a pronounced impact on the superficial and internal structural morphologies of these nanocomposites. These findings may be applicable in devising advanced therapeutic treatments for neurodegenerative diseases and designing novel bio-inorganic magnetic devices. Our results further demonstrate that modern X-ray methods give access to the structure of—and insight into the formation process of—biological–inorganic hybrid structures in solution.

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Advances in Small and Wide‐AngleX‐Ray Scattering from Proteins and Macromolecular Solutions

Spilotros

Gruzinov

Svergun

2019

Encyclopedia of Analytical Chemistry

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Small‐angle scattering of X‐rays (SAXS) is an established method for low‐resolution structural characterization of native biological macromolecules and soft matter objets in solution. Recent progress in instrumentation (most notably, high brilliance synchrotron sources) and novel data analysis methods significantly enhanced the capabilities of the technique for the structure research. SAXS allows one to study the overall static structure and conformational changes in response to variations in external conditions or ligand binding and is able of providing structural information about partially or completely disordered systems. Extending the data collection to wide‐angle X‐ray scattering (WAXS) allows one not only to resolve the overall size and shape of proteins and complexes but also to probe the fold and to analyze subtle structural transitions. In this article, we present the basic aspects of theory and instrumentation as well as the major modeling techniques used in data analysis and interpretation of macromolecular solutions. A brief account of small‐angle neutron scattering technique (SANS) is also presented showing its complementarity to SAXS. Selected applications of SAXS and WAXS to different types of macromolecular solutions are presented including the analysis of dynamic multicomponent equilibria, characterization of flexible systems, and time‐resolved studies.

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Structuralization of magnetic nanoparticles in 5CB liquid crystals

Cited by 26 publications

References 35 publications

Clustering in ferronematics—The effect of magnetic collective ordering

Clustering in ferronematics—The effect of magnetic collective ordering

Dependence of the Nanoscale Composite Morphology of Fe3O4 Nanoparticle-Infused Lysozyme Amyloid Fibrils on Timing of Infusion: A Combined SAXS and AFM Study

Advances in Small and Wide‐AngleX‐Ray Scattering from Proteins and Macromolecular Solutions

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