THERMAL EXPANSION OF SILICA AEROGEL AT LOW TEMPERATURES
A. V. DOLBIN *
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine.
M. V. KHLISTYUCK
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine
V. B. ESELSON
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine.
V. G. GAVRILKO
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine.
N. A. VINNIKOV
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine.
R. M. BASNUKAEVA
Department of Thermal Properties of Molecular Crystals, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkov, 61103, Ukraine.
F. CONCEIÇÃO
Active Aerogels, Lda., Rua Pedro Nunes, IPN Incubadora, (Edif. C), Coimbra 3030-199, Portugal.
M. OCHOA
Active Aerogels, Lda., Rua Pedro Nunes, IPN Incubadora, (Edif. C), Coimbra 3030-199, Portugal.
*Author to whom correspondence should be addressed.
Abstract
Thermal expansion of two silica aerogel samples with different densities has been investigated in the temperature range of 5–290 K. The studies were performed by using a low-temperature capacitive dilatometer. It has been found that the linear thermal expansion coefficient (LTEC) is not monotonic with maximum at the temperature range of 100–150 К. It has been suggested that such behavior is due to the peculiarities of vibrational spectrum of silicon oxide chains.
Keywords: Silica aerogel, linear thermal expansion coefficient (LTEC), vibrational spectrum