Electrosurface Properties of Nanostructured Silica Assessed by EPR of Molecular pH Labels

Verfasser / Beitragende:
[Elena Kovaleva, Leonid Molochnikov, Victoria Osipova, Darya Stepanova, Vladimir Reznikov]
Ort, Verlag, Jahr:
2015
Enthalten in:
Applied Magnetic Resonance, 46/12(2015-12-01), 1367-1382
Format:
Artikel (online)
ID: 605545596
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024 7 0 |a 10.1007/s00723-015-0704-1  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00723-015-0704-1 
245 0 0 |a Electrosurface Properties of Nanostructured Silica Assessed by EPR of Molecular pH Labels  |h [Elektronische Daten]  |c [Elena Kovaleva, Leonid Molochnikov, Victoria Osipova, Darya Stepanova, Vladimir Reznikov] 
520 3 |a Three techniques of spin labeling have been applied to nanostructured SiO2 and have been tested by electron paramagnetic resonance spectroscopy of pH-sensitive nitroxide radicals (NRs). The best technique was based on preliminary interaction of the pH-sensitive NR bromomethyl-2,2,3,5,5-pentamethylimidazoline-1-oxyl with aminopropyltriethoxy-silane (APTES) in the presence of trioctylamine and further treatment of the nanostructured SiO2 with the hydrolyzed product and acetic anhydride. It was found that there are two types of location of the pH-sensitive NRs (spin labels) on the surface of nanostructured silica. The spin labels of the first type located near the surface of nanostructured SiO2 ("slow-motional” NR) have been used to measure near-surface electrical potential at the site of NR N-O• fragment location, q equal to −90mV. The NR molecules of the second type which were positioned well far from the nanostructured SiO2 surface ("fast-motional” NRs) were employed to establish the regularities of mutual changes in the NR form and nanoparticle surface charge with variations in pH of external bulk solution (pHext). The pH-sensitive NRs covalently attached to the SiO2 surface were successfully employed for the study of surface charge in the drying process with a rise of temperature up to 375K. A negative surface charge was shown to decrease due to reducing an ionization degree of the surface silanol groups. This process was found to be reversible at re-adsorption of water molecules. 
540 |a Springer-Verlag Wien, 2015 
700 1 |a Kovaleva  |D Elena  |u Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Mira St., 19, 620002, Yekaterinburg, Russia  |4 aut 
700 1 |a Molochnikov  |D Leonid  |u Department of Chemistry, Ural State Forest Engineering University, Siberian Highway, 37, 620100, Yekaterinburg, Russia  |4 aut 
700 1 |a Osipova  |D Victoria  |u Laboratory of Organic Materials, Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Sofia Kovalevskaya St., 20, Yekaterinburg, Russia  |4 aut 
700 1 |a Stepanova  |D Darya  |u Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Mira St., 19, 620002, Yekaterinburg, Russia  |4 aut 
700 1 |a Reznikov  |D Vladimir  |u Laboratory of Nitroxide Radicals, Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrent'ev Av., 9, 630090, Novosibirsk, Russia  |4 aut 
773 0 |t Applied Magnetic Resonance  |d Springer Vienna  |g 46/12(2015-12-01), 1367-1382  |x 0937-9347  |q 46:12<1367  |1 2015  |2 46  |o 723 
856 4 0 |u https://doi.org/10.1007/s00723-015-0704-1  |q text/html  |z Onlinezugriff via DOI 
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900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
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950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00723-015-0704-1  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Kovaleva  |D Elena  |u Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Mira St., 19, 620002, Yekaterinburg, Russia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Molochnikov  |D Leonid  |u Department of Chemistry, Ural State Forest Engineering University, Siberian Highway, 37, 620100, Yekaterinburg, Russia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Osipova  |D Victoria  |u Laboratory of Organic Materials, Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Sofia Kovalevskaya St., 20, Yekaterinburg, Russia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Stepanova  |D Darya  |u Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Mira St., 19, 620002, Yekaterinburg, Russia  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Reznikov  |D Vladimir  |u Laboratory of Nitroxide Radicals, Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrent'ev Av., 9, 630090, Novosibirsk, Russia  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Applied Magnetic Resonance  |d Springer Vienna  |g 46/12(2015-12-01), 1367-1382  |x 0937-9347  |q 46:12<1367  |1 2015  |2 46  |o 723