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Speranta Tanasescu

Speranta Tanasescu

Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Romania

Title: Particle size versus energetics of nanomaterials: key parameters controlling the stability and reactivity of nanostructured materials


Biography: Speranta Tanasescu


Due to the unique and unusual physical and chemical properties of the systems and structures at the nanoscale, the understanding of their stability and reactivity, presents a host of questions and problems. The dimension-dependent properties or phenomena may be used for functional effects, the nanotechnology taking advantage of this by designing property modifications for applicative reasons. At the same time, research to date suggests that some engineered nanomaterials will present hazards, thus challenging many conventional approaches related to nanosafety area. Because this is an emerging scientific issue, to identify key parameters important for evaluating the possible benefits as well as risks is a central point in the research activity with impact in the materials science. In the present paper will be argued that control of the energetic parameters and the understanding of their crossover when working at the nano-level are important steps in understanding the nanomaterial stability and the possibilities to interaction with the biologic systems. Some compounds from specific systems were selected for discussion: nanostructured transition metal oxides; nanoalloys, bio-nonbio systems. Several conclusions can be drawn from the characterization data obtained so far: •Exploring the relationships between different compositional variables and thermodynamic properties of nanocrystalline transition metal oxides we obtained that particular behavior of these materials could be explained not only qualitatively by the structural changes, but also by the fact that the energetic properties are extremely sensitive to the chemical defects in oxygen sites. •Investigating the metastable phases of Nano alloys synthesized by severe deformation non-equilibrium methods we obtained that the energetic parameters may be used to explain the experimentally observed stability in particular temperature ranges associated with the growth process of nanometer-sized samples. •The evaluation of the thermodynamic parameters describing the nanoparticle - protein interaction is a key issue for the bio-reactivity of nanomaterials having a great impact in nanosafety research


Recent Publications :

  1. Tanasescu S, Maxim F, Neacsu A, Teodorescu F, Milea A, Energetic parameters controlling the stability and reactivity of micro and nanostructured materials (2016), Chapter in Series in Micro and Nanoenginnering, ed. Romanian Academy, Bucharest, pag. 33-50.
  2. Rusti C.F., Badilita V., Sofronia A.M., Taloi D, Anghel E.M., Maxim F, Hornoiu C, Munteanu C, Piticescu R.M., Tanasescu S. (2017) Thermodynamic properties of the Ba0.75Sr0.25TiO3 nanopowders obtained by hydrothermal synthesis 69: 1000-1010
  3. Tanasescu S, Milea A, Gingu O, Maxim F, Hornoiu C, Preda S, Sima G (2015) A Correlation between thermodynamic properties, thermal expansion and electrical resistivity of Ag – 28 % Cu nanopowders processed by mechanical alloying route, Physical Chemistry Chemical Physics 17:28322-28330
  4. Milea A., Gingu O., Preda S., Sima G, Nicolicescu C., Tanasescu S. (2015) Thermodynamic measurements on Ag - 28% Cu nanopowders processed by mechanical alloying route,  Journal of Alloys and Compounds, 629, 214-220
  5. Gingu O., Rotaru P., Milea, A., Marin, A,  Nicolicescu, C., Sima, G., Tanasescu, S. (2015) In-situ synthesis of AgCu/Cu2O nanocomposite by mechanical alloying: The effect of the processing on the thermal behavior, Thermochimica Acta 606, 1-11
  6. Maxim F, Berger D, Teodorescu F, Hornoiu C, Lete C, Tanasescu S (2015) Low-temperature synthesis and thermodynamic and electrical properties of barium titanate nanorods, Journal of Nanomaterials 2015:827641
  7. Maxim F., Poenaru, I., Teodorescu, F., Tanasescu, S. (2014) Barium Titanate Torus-Like Particles: Low-Temperature Synthesis and Formation Mechanism, Eur J Inorg Chem, 30, pp. 5160-5167.
  8. A. SofroniaR. BaiesE. Anghel, C. MarinescuS. Tanasescu (2014) Thermal and structural characterization of synthetic and natural nanocrystalline hydroxyapatite, Materials Science and Engineering: C, 43, 153–163
  9. C. Marinescu, A. Sofronia, C. Rusti, R. Piticescu, V. Badilita, E. Vasile, R. Baies, S. Tanasescu, (2011) DSC investigation of nanocrystalline TiO2 powder, J. Therm. Anal. Calorim. 103:49-57.