Dimitar Shandurkov, Nina Danchova and Denis Paskalev, and Stoyan Gutzov
Sofia University St. Kliment Ohridski, Bulgaria
Posters & Accepted Abstracts: Res. Rev. J Mat. Sci
Sol-gel technology is an advanced physico-chemical method for production of oxide ceramics, glasses, thin film coatings or aerogels. The starting chemicals /liquid precursors as tetraethoxysilane – TEOS/ allow homogenization at molecular level, production of rare chemical compositions and modification of their surface properties [1 - 5]. Aerogels are advanced solid sol-gel materials with extremely low thermal conductivity down to 0.01 W/m K; low density (bellow 0.1 g / cm3) and porosity at about 95%. There are two general strategies for preparation of aerogel particles depending on drying conditions, supercritical and subcritical drying [1, 2]. In the Department of Physical Chemistry, University of Sofia, a novel subcritical preparation scheme based on controlled drying at 0.2-0.5 atm and 40-70 oC was developed. The sol-gel scheme allows preparation both of aerogel microgranules and nanopowders. Recently, we also developed a new technique for incorporation of strongly red emitting complexes / Eu(III) phenanthroline nitrate / into silica aerogels leading to multicolour emiting powders [1, 2]. The technique was also applied to incorporate [Tb(phen)2](NO3)3 and Eu(III) – DMF complexes into aerogel powders. Physicochemical properties of the powders obtained are shown bellow, SBET and Dav are surface area and mean pore diameter, respectively. Cabot Lumira™ aerogel granules (sample 5) are given for comparison.Recent Publications: 1. S. Gutzov, N. Danchova, S. I. Karakashev, M. Khristov, J. Ivanova, J. Ulbikas, Preparation and thermal properties of chemically prepared nanoporous silica aerogels, J Sol-Gel Sci Technol 70 (2014) 511-516. 2. S. Gutzov, N. Danchova, R. Kirilova, V. Petrov, S. Yordanova, Preparation and luminescence of silica aerogel composites containing an europium (III) phenanthroline nitrate complex, Journal of Luminescence 183 (2017) 108–112. 3. J.C.G. Bunzli, On the design of highly luminescent lanthanide complexes, Coordin Chem Rev 293 (2015) 19-47. 4. Preparation and spectral properties of europium hudrogensquarate microcrystals, T. Kolev, N. Danchova, D, Shandurkov, S. Gutzov, submitted to Spectrochimica Acta A (2017) 5. N. Danchova, S. Gutzov, Functionalization of Sol-Gel Zirconia Composites with Europium Complexes, Z Naturforsch B 69(2) (2014) 224-230.
Dimitar Shandurkov studies Physical and theoretical chemistry at the Faculty of Chemistry and Pharmacy, Sofia University “St. Kliment Ohridski”. He possess experience in the sol-get chemistry, hybrid optical materials, obtained at the Department of Physical Chemistry. In addition, he has a strong background in computational chemistry and applied mathematics.