Frank Laboratory of Neutron Physics

Department of Neutron Investigations of Condensed Matter

Topical seminar on nano-structures

Leader – V.L.Aksenov

Date and Time: Friday, 15 February 2019, at 3:00 PM

Venue: DNICM Conference hall, bld. 42а, Frank Laboratory of Neutron Physics

Seminar topic: «Сlusterization aspects of fullerene C₆₀ and C₇₀ in toluene / N-methyl-2-pyrrolidone mixture by SANS, SAXS, UV-Vis and DLS data»

Authors: T.V. Nagornaya^1,2, D. Chudoba^1,3,4, O.A. Kyzyma^1,2, A.V. Nagornyi<sup>1,2

1</sup>Joint Institute for Nuclear Research, Dubna, Russia
²Taras Shevchenko National University of Kyiv, Ukraine
³Adam Mickiewicz University, Poznan, Poland
⁴St Petersburg University, St.Petersburg, Russia

Speaker: T.V. Nagornaya

Abstract:

After discovery of a new allotropic form of carbon – fullerenes, much attention has been paid to possibilities of their applications in various fields, including medicine, photoelectronics and optics [1-3]. Despite of a wide application of fullerene solutions, the processes of their aggregation are still not clear in both weakly polar solvents and their mixtures with polar solvents [4]. It is well-known, that the solubility of fullerenes decreases with increasing polarity of the solvent, and the arising clusterization process is critical and reversible [5]. Fullerene solutions in nitrogen-containing solvents, like pyridine or N-methyl-2-pyrrolidone (NMP) are an exception to the rule.
NMP is a comparatively good solvent for fullerenes and it is also mixable with water. This solvent is suitable for transfering fullerene into aqueous media that is important for employing biological functionalized fullerenes in medical applications [6].
In the present work, the changes in the cluster state of fullerene C₇₀ in NMP solution after toluene addition have been studied. In order to measure the wide range of particle sizes, including sub-single-molecule region and respectively large clusters, the small-angle neutron and X-ray scattering, dynamic light scattering were used. The main task was to find out the correlation between the fullerene clusterization e and a volume concentration of the second nonpolar solvent. It was observed a common dependence of the structure state of fullerene C₇₀ on the polarity of the liquid medium; an increase in toluene content led to dissolution of existing large agglomerates. The obtained data were analyzed in comparison with the previous results on the inverse colloidal system, C₇₀ / toluene / N-methyl-2-pyrrolidone, and, UV-Vis spectroscopy measurements and similar effects in mixtures with C₆₀.

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