Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 13: Topical Session Nanoanalytics using Small-Angle Scattering I

MM 13.3: Vortrag

Dienstag, 24. März 2009, 11:00–11:15, IFW A

Analytical Determination of Micellar Nanoreactor Structure by Means of SANS — •Roza Bakeeva¹, Alexandr Kuklin², and Vladimir Sopin¹ — ¹Kazan State Technological University, Kazan, Russia — ²Joined Institute for Nuclear Research, Dubna, Russia

We have studied the reaction of decomposition of toxic phosphorus esters (O-4-nitrophenyl-O,O-dimethyl-tiophosphate) in micellar media, containing compounds with nucleophilic properties (potassium fluoride KF and sodium hydroxide NaOH). These additives are electrolytes and their addition brings about the reducing a surface potential micelles and it is possible to control the changing of size and form of micelles. In this instance micelle is considered as nanoreactor.

The SANS method was used to determine the characteristic parameters of nanoreactors - micelles (radius, shape, aggregation number). Neutron scattering curves were obtained on YuMO small-angle scattering setup (two-detector version), using a high-efficiency neutron pulse source (IBR-2 reactor). The shape of scattering associates (micelles) was determined by Porod invariant and Guinier plot analyses, as well by simulation using the FITTER program package The most appropriate model of a particle is a sphere for system CTAB + D2O, CTAB + KF + D2O and a cylinder for system CTAB + KF + NaOD + D2O.

The obtained data have shown that introduction KF brings about the compression of micelles CTAB, but addition of NaOH stimulates the sphere to cylinder transition that in the significant measure defines a difference in their catalytic characteristics.