Portail HAL UHA (Université de Haute-Alsace)
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Laser Direct Writing of Crystallized TiO2 by Photothermal Effect Induced by Gold Nanoparticles
No full textInternational audienceAbstractNear‐infrared (NIR) laser annealing is successfully used to crystallize TiO2 thin films from a sol–gel solution deposited on gold nanoparticle arrays (AuNPs). The AuNPs are used as nano‐heaters allowing a local temperature increase up to 500 °C in the film. The temperature reached under the laser is deduced from the presence of the anatase phase in the samples obtained by laser exposure, showing that crystallized TiO2 can be obtained by the photothermal effect. Different analytical techniques supported this study, such as grazing X‐ray diffraction (GIXRD), UV–vis, and Raman spectroscopy. The temperature increase is confirmed by a numerical model that emphasizes the role of NPs coupling in the photothermal effect. Direct laser patterning by NIR laser and in combination with Deep‐UV photolithography (DUV) are demonstrated. This fabrication method opens new perspectives in applications such as photonics, photocatalysis, or biosensing
Narmouthis 2009. Documents découverts à Medinet Madi en 2009 (I)
No full textInternational audienceEdition, translation and study of six documents discovered in Medi- net Madi (Narmouthis) in 2009, during a sand removal campaign (“ripuli- tura”), 2nd-5th centuries A.D
‘If shape it might be called that shape had none’ (Paradise Lost, II.666): Teratological Representations in the Illustrated Editions of Milton’s Paradise Lost from 1688 to 1866
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Endométriose : et si l’activité physique aidait à combattre les symptômes ?
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Sol-gel TiO2 thin film on Au nanoparticles for heterogeneous plasmonic photocatalysis
No full textInternational audienceA new, simple method for preparing substrates for photocatalysis applications under visible light is presented. It is based on the preparation of a dense array of gold nanoparticles (AuNPs) by thermal dewetting of a thin gold film followed by spin-coating of a thin TiO2 film prepared by sol-gel chemistry. The photocatalytic properties of these nanocomposite films are studied by surface enhanced Raman spectroscopy (SERS) following the N-demethylation reaction of methylene blue as a model reaction. This approach shows that the semi-conducting layer on the AuNPs can significantly increase the efficiency of the photo-induced reaction. The SERS study also illustrates the influence of parameters such as TiO2 thickness and position (on or under the AuNPs). Ultimately, this study emphasizes that the primary mechanism behind the Ndemethylation reaction is both the increase of extinction and improved electron transfer facilitated by the semiconducting layer. On the other hand, exclusive reliance on photothermal effects is ruled out.</div
Developpement of environmentally friendly woven textiles for aerosol filtration from residential wood combustion (RWC)
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Biogenic Polymeric Materials from Lignocellulosic Biomass-Derivable 4-Pentenoic Acid and Isosorbide for Potential Biomedical Applications
No full textInternational audienceThe increasing substitution of petroleum-based polymers with materials of biogenic origin is an important step towards the desired circular economy. In fact, research in this area is not only leading to CO2-neutral polymers but is also enabling the development of completely new materials with cell compatibility. Thus, by using the toolbox of lignocellulosic biomass derivatives (in particular, isosorbide and 4-pentenoic acid; the latter being less explored and recognized in the field of synthetic polymer chemistry), acyclic diene metathesis polymerization has been explored for the synthesis of the biogenic polymer derivative. Upon characterizing the chemical structure of the 100% “biomass-derived” polyester derivative by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), and attenuated total reflectance infrared (ATR-IR) spectroscopy, we have explored the thermal properties via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The DSC study has revealed that the polymer exhibits a glass transition temperature (Tg) value of 17 °C, thus reflecting an amorphous behavior. The mechanical properties and cell compatibility of the polyester derivative were also evaluated by dynamic mechanical analysis (DMA) and a cytotoxicity test. By assessing the cytotoxicity of the functional novel polyester derivative, we were able to reflect the benefit of employing isosorbide and 4-pentenoic acid as building blocks for materials with potential biomedical applications (in particular, as a new cartilage material)