UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-22 2:37
 HOME     CONFERENCES     SEARCH            LOGIN     NEW USER     IMAGES   


Conference: Bucharest University Faculty of Physics 2007 Meeting


Section: Solid State Physics and Materials Science


Title:
Nanostructured Bioglass Thin Films for Medical Applications


Authors:
C. Berbecaru1, H. V. Alexandru1, Cristescu Luminita1, C. Morosanu2, A. Slav2, G. Stan2, D. Marcov2, Adelina Ianculescu3, A. Popescu4, G. Socol4, F. Sima4, I. Mihailescu4


Affiliation:
1. University of Bucharest, Faculty of Physics,

2. National Institute of Materials Physics (NIMP),

3. “Politehnica” University of Bucharest,

4. National Institute for Lasers Plasma and Radiation Physics.


E-mail


Keywords:


Abstract:
Thin films using bioglass (BG) targets have been prepared by pulsed laser deposition (PLD) and magnetron sputtering (MS) methods [1]. Three types of powders with different silica content were used (54, 57 and 61 %). Titanium alloys, silicon and quartz were used as substrates for micrometer thin films deposition. PLD films were obtained in a crystalline state by heating the support at 450 oC during deposition. MS layers showed an amorphous structure, even after post annealing at 750 oC in air. Film surface, as evidenced by SEM analysis, displayed “droplets” structured at nano-micro level which is quite unusual in case of magnetron sputtering method. The PLD films displayed a typical surface with nanometric droplets embedded in the film. The stoechiometry of the targets was preserved for the PLD films but was much more different for MS depositions. An increase of phosphorus ratio was noticed versus the silicon ones. The behavior of thin layers in simulated body fluids (SBF) was tested using chemical growth experiments. Sample was removed from SBF successively after 1, 3, 7, 14, 21 days. Films surface changes were monitored by FTIR, SEM and XRD analysis. The chemical phenomena could be explained by dissolution and precipitation processes at the solid liquid interface due to an ionic exchange between BG and SBF. This growth mechanism is quite similar to those noticed in the case of in-growth onto crystalline and amorphous hydroxyapatite sputtered films [2]. In order to increase film-substrate adhesion, functional graded compositional structure was also prepared by magnetron co-sputtering, using titanium and bioglass targets. The efficiency of the procedure was demonstrated by the “pull method” of the thin layers. References: [1] Mihailescu at all, EUREKA E 3033 WORKSHOP, Bucuresti-Sinaia,January 15-18, 2006, [2] Liliana Verestiuc et all, J Cryst. Growth 264 (2004) 483.