Ceramics-Silikáty 39, (2) 69 - 72 (1995) |
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WETNESS EFFECT ON EPR Cu(II) SPIN LABEL IN HEAT TREATED SILICA XEROGELS |
Liška Marek 1, Mazúr Milan 2, Hulínová Hana 1,
Pelikán Peter 2,
Valko Marián 2,
Nerád Ivan 1 |
1 Institute of Inorganic Chemistry, Slovak Academy of Sciences, Martina Rázusa, 911 01 Trenčín, Slovak Republic
2 Department of Physical Chemistry, Faculty of Chemical Technology,
Slovak Technical University, 812 37 Bratislava, Slovak Republic
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The present paper deals with drying of SiO₂ xerogel that leads to the decrease of the intensity of Cu(ll) spin probe EPR signal and to the signa/noise ratio as well. This effect is explained by changes of Cu(II) coordination into an EPR less sensitive one. During a sample dehydration the decrease of electric permittivity causes the increase of the dipole interaction between Cu(II) coordination polyhedral, which plays an important role in decreasing EPR signal. |
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