Adina Iuliana Amironesei

Publications

• Layered Silicone - Silver Composites

  ADINA IULIANA AMIRONESEI, CLAUDIA TABACARU, ION SANDU, MARIA CAZACU, GHEORGHE I. RUSU, FELICIA IACOMI

  CHEMISTRY MAGAZINE. 01/2011; 4:455.

  Some composites based on silicone matrix and silver particles have been prepared by mixing a prehydrolysate based on three silanes (methyltrimethoxysilane, MTES, dimethyldiethoxysilane, DMDES, and 3-aminopropyltriethoxysilane, APTES) with a freshly prepared silver nitrate solution in dimethylformami... [more] Some composites based on silicone matrix and silver particles have been prepared by mixing a prehydrolysate based on three silanes (methyltrimethoxysilane, MTES, dimethyldiethoxysilane, DMDES, and 3-aminopropyltriethoxysilane, APTES) with a freshly prepared silver nitrate solution in dimethylformamide (DMF) or deionized water. X-Ray diffraction, scanning electron microscopy, electron paramagnetic resonance, optical and electrical investigations evidenced that the nature and the size of formed nanoparticles is influenced not only by the salt concentration or solution nature (DMF or aqueous environment), but also by DMF/H2O and DMF/APTES molar ratios.

• The Meyer-Neldel rule in layered silicone-silver nanocomposites

  A. Yildiz, F. Iacomi, M. Cazacu, A. Amironesei, G.I. Rusu, S. Simon

  Polymer Composites. 01/2011; Volume 32:Pages: 1751–1756.

  X-Ray diffraction and X-ray photoelectron spectroscopy studies, applied on some silicone-silver nanocomposites, revealed the influence of the solvent used in preparation on the morphology of the resulted materials. It has been emphasized that dimethylformamide solvent favors the formation of silver ... [more] X-Ray diffraction and X-ray photoelectron spectroscopy studies, applied on some silicone-silver nanocomposites, revealed the influence of the solvent used in preparation on the morphology of the resulted materials. It has been emphasized that dimethylformamide solvent favors the formation of silver nanoparticles and their migration at the surface, while water solvent favors the formation of a homogeneous composite with small silver nanoparticles. The places occupied by Ag nanoparticles (some prevent their oxidation and others that favor the oxidation process) are dependent on the mixture used in sol-gel technique and have influence on the nanocomposite electrical conductivity. The temperature dependence of the electrical conductivity is investigated. A linear relationship between the pre-exponential factor (σ0) and activation energy (Ea) was observed, in the high temperature range (T > 315 K), for all the samples, indicating that the conductivity data obey Meyer-Neldel rule.

• Studies on the electrical and optical properties of some polyazomethine thin films prepared by a spin-coating method

  A. AMIRONESEI, A. AIRINEI, D. TIMPU, V. COZAN, A. P. RAMBU, M. IRIMIA, F. IACOMI, G. I. RUSU

  JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS. 01/2011; 13:802.

  Three types of polymers containing azomethine units linked by ether bond, sulfone and bisfenols, were prepared, dissolved in dimethylformamide and deposited on glass slides by spin coating. The obtained transparent thin films exhibit an amorphous structure with morphology dependent on chemical struc... [more] Three types of polymers containing azomethine units linked by ether bond, sulfone and bisfenols, were prepared, dissolved in dimethylformamide and deposited on glass slides by spin coating. The obtained transparent thin films exhibit an amorphous structure with morphology dependent on chemical structure. The study of optical absorption evidenced large direct band gaps. The sulfone presence induces an increase in the thin film band gap energy and a decrease in Urbach energy and low-energy absorption coefficient. The temperature dependence of the electrical conductivity showed that thin films have semiconducting properties with two distinct sections. The mechanism of electronic transport is described. The values of the energy band gap determined from absorption spectra were in good agreement with those calculated from the temperature dependence of the electrical conductivity. In the low temperature range, the temperature dependence of the electrical conductivity was described by the Mott variable range hopping model.