Temperature-dependent fractal structure of particle clusters in aqueous ferrofluids by small-angle scattering

0541431 - ÚJF 2022 RIV NL eng J - Journal Article
Tomchuk, O. V. - Avdeev, M. V. - Aksenov, V. L. - Shulenina, A. V. - Ivankov, O. I. - Ryukhtin, Vasil - Vekas, L. - Bulavin, L. A.
Temperature-dependent fractal structure of particle clusters in aqueous ferrofluids by small-angle scattering.
Colloids and Surfaces A-Physicochemical and Engineering Aspects. Roč. 613, MAR (2021), č. článku 126090. ISSN 0927-7757. E-ISSN 1873-4359
R&D Projects: GA MŠMT LTT18021
Research Infrastructure: CANAM II - 90056; Reactors LVR-15 and LR-0 II - 90120
Institutional support: RVO:61389005
Keywords : aqueous ferrofluids * fractal aggregation * temperature-induced reorganization * small-angle scattering * contrast variation * poldispersity analysis
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 5.518, year: 2021
Method of publishing: Limited access
https://doi.org/10.1016/j.colsurfa.2020.126090

The heating effect in the temperature interval of 20-70 degrees C on the aggregate structure in aqueous ferrofluids is analyzed basing on the data of small-angle X-ray (SAXS) and neutron (SANS) scattering. Samples prepared according to the same stabilization procedure (double-layer surfactant coating) but with different dispersed magnetic materials (magnetite and cobalt ferrite) show different temperature sensitivity. A temperature-induced reorganization from developed aggregates to elongated chain-like aggregates is revealed by observing changes in the scattering curves, which are considered in the frame of the fractal concept. In addition to the determination of fractal dimension, the accent is also given to the cut-off effect in the scattering curves induced by the finite aggregate size. The scattering model is chosen from the available approaches basing on the analysis of the dimension-dependent universal parameter of the average aggregate form-factor, which continuously changes with varying temperature. The particle polydispersity is taken into account. The contrast variation based on isotope (H/D) substitution in solvent is done in SANS experiments to conclude about the structural organization of magnetic particles and surfactant component in the systems.
Permanent Link: http://hdl.handle.net/11104/0318989