Marjorie Olivier

Effect of photo-crosslinking on the performance of silica nanoparticle-filled epoxidized acrylic copolymer coatings

The effect of UV-crosslinking on the morphological, mechanical and barrier properties of a hybrid coating based on an epoxidized acrylic polymer filled with silica nanoparticles, incorporated in situ through the sol–gel method, was studied. A systematic comparison of coatings loaded with various amounts of silica nanoparticles subjected or not to UV-curing was reported. The morphological and mechanical properties were investigated by atomic force microscopy (AFM) and tribology tests, while the corrosion resistance of thin films applied on aluminum alloys was measured by electrochemical impedance spectroscopy (EIS). Our findings indicate that a synergic effect is brought about by the combination of silica nanoparticles and UV-curing, significantly enhancing the mechanical properties of the coating, although the corrosion protection was compromised. The resulting coating may be used in applications requiring high mechanical performance.

Development of mesoporous sol–gel films for antifingerprint applications on glass

AbstractMesoporous films were synthesized by specific sol–gel route, including the use of surfactant molecules acting as templating agent through the evaporation induced self-assembly process. Controlled mesoporosity of the film is obtained by the thermal removal of the templating agent. In this work, the mesostructure of the sol–gel layer is used as reservoir for active enzymatic molecules providing antifingerprint coating. The mesopore size and their configuration were designed to assure a good impregnation by lipases. The coatings were applied on glass. The influence of the deposition process and the composition of the sol–gel on the structure of the mesoporous film was investigated. The film morphology was characterized by scanning electron microscopy and water adsorption/desorption isotherms recorded with a quartz crystal microbalance. The stability of the sol–gel solution was assessed by rheological measurements. The efficiency of the combination of mesoporous film and the enzymatic solution was determined in terms of antifingerprint properties using an artificial sebum. Mesoporous sol–gel film is used as reservoir for active enzymatic biomolecules to provide antifingerprint coating. Mesoporous structure is obtained by the sol–gel method using the evaporation induced self-assembly process. Different parameters (thickness of coating, concentration in templating agent, etc.) were studied to manage and adapt the size and the structure of the mesopores in order to obtain an active coating.HighlightsDesign of mesoporous sol–gel films using evaporation induced self-assembly process.Influence of the thickness, deposition method, and templating agent/precursor molar ratio on the mesoporosity.Evaluation of antifingerprint properties of the sol–gel films impregnated with enzymes.

Improvement of Mechanical and Dielectric Properties of Epoxy Resin Using CNTs/ZnO Nanocomposite

In this study, carbon nanotubes (CNTs)/ZnO composites had been prepared using the sol-gel method and then incorporated into an epoxy resin for reinforcement of mechanical and electrical properties. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) Field Emission Scanning Electron Microscope (FE-SEM) analyses show that the ZnO nanoparticles deposited on CNTs were crystallized in a hexagonal wurtzite structure. Average particle size of ZnO deposited on the CNT was about 8 nm. The mechanical and dielectric properties of epoxy containing CNTs/ZnO were investigated in comparison to epoxy resin and epoxy resin containing only CNT or ZnO nanoparticles. The results indicated that tensile strength and elongation at break of the nanocomposite were substantially improved with the presence of CNTs/ZnO at the equal volume. The DSC analysis associate with the dielectric results shows that the behavior of epoxy/CNTs/ZnO is identical to epoxy/ZnO composite, and the CNTs is essential to the distributed arrangement of ZnO in the epoxy resin.

Infrared Radiation Detection Using Fiber Bragg Grating

Optical fiber sensors bring to measurement systems all the advantages offered by the optical fiber technology. In particular, their low weight and small dimensions yield non-intrusive capabilities while their immunity against electromagnetic interference leads to usefulness in harsh environments. Among the various optical fiber sensor configurations, fiber Bragg gratings (FBGs) are particularly interesting, especially thanks to their wavelength-encoded response and their inherent multiplexing capability. They can be used to measure static and dynamic perturbations such as temperature (Crunelle et al., 2009; Fernandez-Valdivielso et al., 2002), mechanical strain (Han, 2009; Ho, 2002) and pressure (Sheng et al., 2004). Their association with a sensitive layer converting themeasurand into a local stress or a temperature elevation around the FBGs drastically increases the panel of applications.

Improvement in selectivity of NO 2 sensors based on WO 3 thin films with MnO 2 filters deposited by radio frequency sputtering

Thin-film WO<inf>3</inf> sensor with a MnO<inf>2</inf> filter was prepared to reduce interference of O<inf>3</inf> for NO<inf>2</inf> detection. The multi-films (WO<inf>3</inf> film, MnO<inf>2</inf> filter and WO<inf>3</inf>+MnO<inf>2</inf> insulting layer) were deposited by radio frequency sputtering. The microstructure and crystalline phase of the films were characterized with SEM and XRD. The sensors were tested for 25–200 ppb O<inf>3</inf> and 50–400 ppb NO<inf>2</inf> in moist air at temperatures ranging from 150°C to 250°C. The results show that the sensors with thin filters are capable to reduce the interference from O<inf>3</inf>.