"Etude et synthèse des nanostructures pour application en biomédicale et environnementale"

Abstract

"This thesis has two main parts: the first part relates to the synthesis and the functionalization of silver nanoparticles (NPs) and zinc oxide NPs, while the second was devoted for deposing titanium nitride (TiN), titanium carbide (TiC) and carbon doped titanium nitride C-TiN coatings able to protect a metallic implant against aggressive liquids such as blood. Due to their remarkable Antibacterial properties, silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) have been widely used in the antimicrobial field. In this work, Ag NPs and ZnO Qds were synthesized using polyol and hydrothermal method, respectively. The obtained colloids were characterized using UV–visible spectroscopy, Raman spectrometry, XRD, TEM, HRTEM, AFM and XPS. The Ag NPs exert their antibacterial activities mainly by the released Ag+. It was demonstrated that Ag NPs can be oxidized easily in aqueous solution and the addition of acetic acid can increase the Ag+ release which improves the antibacterial activity of Ag NPs. A comparative study between Ag NPs/acetic acid and Ag NPs/ZnO Qds bactericidal effect on pseudomonas aeruginosa, escherichia coli, klebsiella pneumonia and staphylococcus aureus was undertaken using agar diffusion method (Kirby-Bauer). In the second part of this work, titanium carbide and titanium nitride as well as carbon doped titanium nitride were obtained by RF magnetron sputtering. This process allowed the elaboration of coatings for protecting an orthopedic implant against an aggressive medium such as tissue environment. The influence of several experimental parameters and in particular the partial pressures of the reactive gases has been studied on the chemical composition, the constituent phases and the electrochemical behavior of coatings."