Artem Feoktystov

Forschungszentrum Jülich

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Vitaliy Pipich

Heinz Maier-Leibnitz Zentrum

Thomas Brückel

Forschungszentrum Jülich

МВ

М. В. Авдеев

Joint Institute for Nuclear Research

Lester C. Barnsley

Australian Synchrotron

Vasil M. Garamus

Helmholtz-Zentrum Hereon

Nileena Nandakumaran

University of Minnesota

Mikhail Feygenson

Forschungszentrum Jülich

Earl Babcock

Forschungszentrum Jülich

Zahir Salhi

Heinz Maier-Leibnitz Zentrum

L. Vékás

Romanian Academy

Cooperative Institutions

Forschungszentrum Jülich

Heinz Maier-Leibnitz Zentrum

RWTH Aachen University

Centre National de la Recherche Scientifique

Stadtwerke Jülich (Germany)

Institut Laue-Langevin

Technische Universität Berlin

Technical University of Munich

Max Planck Computing and Data Facility

Slovak Academy of Sciences

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Mesoscopic Correlation Functions in Heterogeneous Ionic Liquids

The Journal of Physical Chemistry B (2016)

Henning Weiss Julian Mars Hailong Li Gunnar Kircher Oxana Ivanova

A common feature of ionic liquids composed of cations with long aliphatic side chains is structural heterogeneities on the nanometer length scale. This so-called microphase separation arises from the clustering of aliphatic moieties. The temperature dependence of the liquid bulk structure was studied by small-angle X-ray and neutron scattering for a set of methylimidazolium ([C18C1im]+, [C22C1im]+) based ionic liquids with tris(pentafluoroethyl)trifluorophosphate ([FAP]-), bis(trifluoromethylsulfonyl)imide ([NTf2]-), and bis(nonafluorobutylsulfonyl)imide ([NNf2]-) anions. The experimental data is quantitatively analyzed using a generalized Teubner-Strey model. Discussion of the resulting periodicity d and correlation length ξ shows that the structural heterogeneities are governed by the interplay between the alkyl chain length, the geometry of the anion, and entropic effects. Connections between the mesoscopic correlation functions, density, and entropy of fusion are discussed in comparison to alcohols. The observed dependencies allow predictions on the mesoscopic correlation functions based on macroscopic bulk quantities.

Mesoscopic physics

Imide

10.1021/acs.jpcb.6b11220

Cite

Citations (44)

Field-induced self-assembly of iron oxide nanoparticles investigated using small-angle neutron scattering

Nanoscale (2016)

Zhendong Fu Yinguo Xiao Artem Feoktystov Vitaliy Pipich Marie‐Sousai Appavou

The magnetic-field-induced assembly of magnetic nanoparticles (NPs) provides a unique and flexible strategy in the design and fabrication of functional nanostructures and devices. We have investigated the field-induced self-assembly of core-shell iron oxide NPs dispersed in toluene by means of small-angle neutron scattering (SANS). The form factor of the core-shell NPs was characterized and analyzed using SANS with polarized neutrons. Large-scale aggregates of iron oxide NPs formed above 0.02 T as indicated by very-small-angle neutron scattering measurements. A three-dimensional long-range ordered superlattice of iron oxide NPs was revealed under the application of a moderate magnetic field. The crystal structure of the superlattice has been identified to be face-centred cubic.

Small-Angle Scattering

Iron oxide nanoparticles

10.1039/c6nr06275j

Cite

Citations (38)

Signature of antiphase boundaries in iron oxide nanoparticles

Journal of Applied Crystallography (2021)

Tobias Köhler Artem Feoktystov O. Petracic Nileena Nandakumaran Antonio Cervellino

Iron oxide nanoparticles find a wide variety of applications, including targeted drug delivery and hyperthermia in advanced cancer treatment methods. An important property of these particles is their maximum net magnetization, which has been repeatedly reported to be drastically lower than the bulk reference value. Previous studies have shown that planar lattice defects known as antiphase boundaries (APBs) have an important influence on the particle magnetization. The influence of APBs on the atomic spin structure of nanoparticles with the γ-Fe2O3 composition is examined via Monte Carlo simulations, explicitly considering dipole-dipole interactions between the magnetic moments that have previously only been approximated. For a single APB passing through the particle centre, a reduction in the magnetization of 3.9% (for 9 nm particles) to 7.9% (for 5 nm particles) is found in saturation fields of 1.5 T compared with a particle without this defect. Additionally, on the basis of Debye scattering equation simulations, the influence of APBs on X-ray powder diffraction patterns is shown. The Fourier transform of the APB peak profile is developed to be used in a whole powder pattern modelling approach to determine the presence of APBs and quantify them by fits to powder diffraction patterns. This is demonstrated on experimental data, where it could be shown that the number of APBs is related to the observed reduction in magnetization.

Debye

Particle (ecology)

10.1107/s1600576721010128

Cite

Citations (10)

Laponite/poly(2-methyl-2-oxazoline) hydrogels: Interplay between local structure and rheological behaviour

Journal of Colloid and Interface Science (2020)

Clémence Le Cœur Cédric Lorthioir Artem Feoktystov Baohu Wu Gisèle Volet

10.1016/j.jcis.2020.07.068

Cite

Citations (17)

Magnetic investigations on irradiation-induced nanoscale precipitation in reactor pressure vessel steels: A first-order reversal curve study

Journal of Nuclear Materials (2021)

Satoru Kobayashi Hiroaki Murakami Takuya Yamamoto G.R. Odette Ákos Horváth

Hysteresis

10.1016/j.jnucmat.2021.152973

Cite

Citations (1)

Small-angle neutron scattering contrast variation on magnetite-myristic acid-benzene magnetic fluid

Journal of Surface Investigation X-ray Synchrotron and Neutron Techniques (2009)

Artem Feoktystov М. В. Авдеев В. Л. Аксенов Л. А. Булавин D. Bica

Myristic acid

10.1134/s1027451009010017

Cite

Citations (7)

Aggregation Behavior of Nonsymmetrically End-Capped Thermoresponsive Block Copolymers in Aqueous Solutions: Between Polymer Coils and Micellar States

Macromolecules (2022)

Albert Prause Michelle Hechenbichler Benjamin von Lospichl Artem Feoktystov Ralf Schweins

The thermosensitive aggregation behavior in an aqueous solution of a library of amphiphilic BAB* copolymers is studied, where "A" represents a long permanently hydrophilic poly(N,N-dimethylacrylamide) (pDMAm) block, "B" represents a permanently hydrophobic end with an n-dodecyl chain, and "B*" represents a thermoresponsive (TR) block featuring a lower critical solution temperature (LCST). Four polyacrylamides are employed for B*, namely, poly(N-n-propylacrylamide) (pNPAm), poly(N-isopropylacrylamide) (pNiPAm), poly(N,N-diethylacrylamide) (pDEAm), and poly(N-acryloylpyrrolidine) (pNAP), which differ with respect to the hydrophilicity of their amide side chains and LCST behavior. While blocks A and B were kept constant, the lengths of the TR blocks were varied systematically. These amphiphilic copolymers were studied as a function of concentration and temperature via light and neutron scattering (static light scattering (SLS), dynamic light scattering (DLS), small-angle neutron scattering (SANS)). For sufficiently long pNiPAM and pDEAm blocks (DPn > 40), a pronounced hydrophobic effect at temperatures above the LCST transition results in well-structured, ordered aggregates. Thus, the aggregation can be controlled by the choice and length of the TR block, thereby elucidating a so far hardly explored class of temperature-sensitive polymeric amphiphiles.

Poly(N-isopropylacrylamide)

10.1021/acs.macromol.2c00878

Cite

Citations (8)

Creating a synthetic platform for the encapsulation of nanocrystals with covalently bound polymer shells

Nanoscale (2019)

Rieke Koll Lisa Fruhner Hauke Heller Jürgen Allgaier Wim Pyckhout‐Hintzen

We present a platform for the encapsulation of superparamagnetic iron oxide nanocrystals (SPIONs) with a highly stable diblock copolymer shell allowing a homogeneous dispersion of the nanocrystals into a polymer matrix in the resulting nanocomposites. High polymer shell stability was achieved by crosslinking the inner polydiene shell for example in a persulfate based redox process. The advantage of this crosslinking reaction is the avoidance of heat and UV light for the initiation, making it suitable for heat or UV sensitive systems. In addition, we were able to minimize the ligand excess needed for the encapsulation and showcased a variation of molecular weight and composition as well as different ligands which lead to stable micelles. The encapsulated nanocrystals as well as the nanocomposite materials were characterized by transmission electron microscopy (TEM) and small angle scattering (SAXS and SANS).

Small-angle X-ray scattering

Superparamagnetism

10.1039/c8nr10018g

Cite

Citations (12)

Confinement Facilitated Protein Stabilization As Investigated by Small-Angle Neutron Scattering

Journal of the American Chemical Society (2018)

Justin Siefker Ralf Biehl Margarita Kruteva Artem Feoktystov Marc‐Olivier Coppens

While mesoporous silicas have been shown to be a compelling candidate for drug delivery and the implementation of biotechnological applications requiring protein confinement and immobilization, the understanding of protein behavior upon physical adsorption into silica pores is limited. Many indirect methods are available to assess general adsorbed protein stability, such as Fourier-transform infrared spectroscopy and activity assays. However, the limitation of these methods is that spatial protein arrangement within the pores cannot be assessed. Mesoporous silicas pose a distinct challenge to direct methods, such as transmission electron microscopy, which lacks the contrast and resolution required to adequately observe immobilized protein structure, and nuclear magnetic resonance, which is computationally intensive and requires knowledge of the primary structure a priori. Small-angle neutron scattering can surmount these limitations and observe spatial protein arrangement within pores. Hereby, we observe the stabilization of fluid-like protein arrangement, facilitated by geometry-dependent crowding effects in cylindrical pores of ordered mesoporous silica, SBA-15. Stabilization is induced from a fluid-like structure factor, which is observed for samples at maximum protein loading in SBA-15 with pore diameters of 6.4 and 8.1 nm. Application of this effect for prevention of irreversible aggregation in high concentration environments is proposed.

10.1021/jacs.8b08454

Cite

Citations (28)

Nanostructure of HT-PEFC Electrodes Investigated with Scattering Methods

ECS Transactions (2017)

Olaf Holderer Marina Khaneft Yu Lin Shuai Liu Artem Feoktystov

The nanostructure of the electrode layer of a HT-PEFC is studied with neutron and X-ray small-angle scattering techniques. The different contrasts of the two probes provide a view on different aspects of the electrode layer. In combination with contrast variation by H-D isotope exchange further insight into the distribution of the different components on length scales in the range of 1-100 nm is obtained. An outlook shows the perspectives of scattering techniques for studying proton diffusion in such heterogeneous materials.

10.1149/08008.0019ecst

Cite

Citations (4)