Nanopores in Silica Aerogels
O. Šauša a, M. Iskrová a, V. Majerník a, J. Krištiak a, K. Jesenák b and M. Vargová b
a Institute of Physics of SAS, D'ubravskácesta 9, 854 11 Bratislava, Slovakia
b Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, MlynskáDolina CH-2, 842 15 Bratislava, Slovakia
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Received: 3 09 2007;
The size of nanopores in thermally treated samples of silica aerogels was determined by ortho-positronium lifetime measurements at room temperature. The annealing of samples in the temperature region of 300-800°C does not make substantial changes in pore size felt by positronium. The annealing at higher temperatures from an interval of 800-1050°C causes shrinkage of the samples reducing the pore size to 1-15 nm. The macropores vanish at temperature treatment at 1000°C and the positron annihilation is not affected by oxygen from air.
DOI: 10.12693/APhysPolA.113.1517
PACS numbers: 78.70.Bj