Sylvie ETIENNE - Academia.edu (original) (raw)

Papers by Sylvie ETIENNE

ACS Sustainable Chemistry & Engineering, 2016

A new monolithic carbonaceous material, 750-HMF-CarboHIPE is presented here. The new electrode ha... more A new monolithic carbonaceous material, 750-HMF-CarboHIPE is presented here. The new electrode has been tested as an anode material inside a microbial bioelectrochemical system. In a purposely designed continuous flow bioelectrochemical reactor, the new material showed high biocompatibilty, with a continuous biofilm development that remained bioelectrochemically active for over 5 months. A catalytic current of 1.56 mA cm-2 / 7.8 mA cm-3 (normalization by projected surface area and volumetric current) was reached. The current density was proportional to the flow rate. The new electrode material was synthesized using a high internal phase emulsion (HIPE) as a soft template to confine the polymerization and hydrothermal carbonization of two precursors derived from the cellulosic fraction of biomass and the bark of fruit trees: respectively, 5-hydroxymethylfurfural and phloroglucinol. All together, the sustainable synthetic route from biomass materials and the proposed application of oxidizing organic matter present in wastewater to produce electricity in a microbial fuel cell (MFC) close an interesting loop of prospective sustainable technology.

RSC Adv., 2016

A chemically amplified photosensitive organic–inorganic hybrid material based on PAA polymer, TVE... more A chemically amplified photosensitive organic–inorganic hybrid material based on PAA polymer, TVEB as a crosslinking dissolution inhibitor, a VEPTES pre-hydrolysed as an organic–inorganic material and a PAG photoacid generator was developed.

Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective... more Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective to understand the mechanical behavior of these highly porous solids. The mechanical behaviour of gels is described in terms of elastic and brittle materials, like glasses or ceramics. The magnitude of the elastic and rupture modulus is several orders of magnitude lower compared to dense glass. The mechanical behaviours (elastic Gels 2015, 1 2 and brittle) are related to the same kinds of gel characteristics: pore volume, silanol content and pore size. Elastic modulus depends strongly on the volume fraction of pores and on the condensation reaction between silanols. Concerning the brittleness features: rupture modulus and toughness, it is shown that pores size plays an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size is related to the pore size. Weibull's theory is used to show the statistical nature of flaw. Moreover, stress corrosion behaviour is studied as a function of environmental conditions (water and alcoholic atmosphere) and temperature.

Matériaux & Techniques, 2015

Les materiaux poreux couvrent un champ scientifique et technologique multidisciplinaire tres larg... more Les materiaux poreux couvrent un champ scientifique et technologique multidisciplinaire tres large. Ils sont mis en œuvre dans de nombreux dispositifs et procedes existants ou emergents, lies a de forts enjeux societaux tant en termes environnementaux qu’economiques. Notre choix a ete d’illustrer les avancees dans le domaine des materiaux poreux au travers de trois exemples specifiques : celui de l’ingenierie des materiaux poreux avec le cas de mesoporeux organiques prepares a partir de polymeres a blocs, celui de l’utilisation de la modelisation et de la simulation numerique avec le cas de l’adsorption d’especes moleculaires a l’echelle nanometrique, et enfin celui des applications technologiques avec le cas des isolants thermiques.

Acknowledgements: research leading to these results was funded within the 7th EU Framework Progra... more Acknowledgements: research leading to these results was funded within the 7th EU Framework Program, (FP7/2007-2013), under grant agreement n°260141, AEROCOINS project, and French National Research Agency (ANR), project “Nanocel” ANR-09-HABISOL-010.

The European Physical Journal Special Topics, 2015

Procédé de fabrication d'un élément optique comprenant à sa surface des cellules remplies d&#... more Procédé de fabrication d'un élément optique comprenant à sa surface des cellules remplies d'un aérogel qui ne se fissure ni lors de sa fabrication, ni lors d'une étape postérieure d'imprégnation de l'aérogel par un liquide. La présente invention a également pour objet les éléments optiques susceptibles d'être obtenus par ce procédé.

RSC Advances, 2014

ABSTRACT Organic-inorganic hybrid material was synthesized by double polymerization processes i.e... more ABSTRACT Organic-inorganic hybrid material was synthesized by double polymerization processes i.e. a sol-gel process and organic polymerization respectively. For this study, hybrid monomer, 4-vinyl ether-phenyltriethoxysilane (VEPTES) was used as starting building block. First, the silica matrix with tunable ratio of siloxane and silanol units was synthesized by a sol-gel process under acidic conditions and the organic network was formed by cationic photopolymerization of vinyl ether groups. Mineral and organic polymerization kinetics were respectively monitored by liquid 29Si-NMR and IR spectroscopy. The effect of the silicate backbone on the organic photopolymerization process was studied and elucidated. The optical performance of this new hybrid material has been studied using the near-infrared spectroscopy.

Microporous and Mesoporous Materials, 2014

ABSTRACT We measured gas and water permeability in sets of nano-composite silica gels, (silica ge... more ABSTRACT We measured gas and water permeability in sets of nano-composite silica gels, (silica gel network with aerosil particles), which are highly porous but low permeability materials. Experimental results showed that gas and liquid permeability increased with aerosil content, allowing control of transport properties. Our results also showed that gas permeability was more than one order of magnitude higher than water permeability. This difference was analysed in view of the gas slippage effect. To this end, we tested and compared different correction factor models (Knudsen and Klinkenberg correction factors) proposed in the literature. We showed that the Klinkenberg factor increases with porosity, and discuss the effect of tortuosity. Models that account for porosity and tortuosity improve the accuracy of the prediction. The Knudsen correction increased the accuracy of the experimental data and made it possible to extrapolate the intrinsic permeability from the gas permeability with quite reasonable accuracy.

Biomacromolecules, 2014

Monolithic pectin aerogels, aeropectins, were prepared via dissolution-gelation-coagulation and s... more Monolithic pectin aerogels, aeropectins, were prepared via dissolution-gelation-coagulation and subsequent drying with supercritical CO2. Aeropectin had pore sizes that varied from mesopores to small macropores and compression moduli in the range from 4 to 18 MPa. Aeropectins show plastic deformation up to 60% strain before the pore walls collapse. Pectin aerogels have a thermal conductivity below that of air in ambient conditions, making them new thermal superinsulating fully biomass-based materials. The contribution of gas and solid conduction plus radiative heat transfer were determined and discussed.

Journal of the American College of Cardiology, 1997

Journal of Sol-Gel Science and Technology, 2011

In order to improve the mechanical properties of silica aerogels, we propose the synthesis of nan... more In order to improve the mechanical properties of silica aerogels, we propose the synthesis of nano composite aerogels. Silica particles (20-100 nm) are added in the monomer solution, just before gelling and supercritical drying. The silica particles addition increases the mechanical properties, but also affects the aggregation process, the aerogel structure and the pore sizes. We discuss the different parameters which infer in the mechanical behaviour of silica aerogel such as: brittle behaviour, load bearing fraction of solid (pore volume), internal stresses (shrinkage), size and distribution of flaws, subcritical flaws propagation (chemical susceptibility). With silica particles addition, the mechanical properties rapidly increase, stiffening and strengthening the structure by a factor 4-8. Moreover, the mechanical strength distribution and the Weibull modulus characterizing the statistical nature of flaws size in brittle materials show a more homogeneous strength distribution. The composite structure is made of two imbricate networks, the polymeric silica and the particles silica networks. Ultra Small Angle X-ray Scattering experiments show that besides the fractal network usually built up by the organosiloxane, the silica particles is forming another fractal structure at a higher scale. The fractal structure could be related to the low Weibull parameter characteristic of a large flaws size distribution, pores being the critical flaws. Keywords Aerogels Á Composites Á Mechanical properties Á Weibull modulus Á Fractal 1 Introduction Aerogels have drawn increasing interest in different fields from their use in fundamental physics research to their application as specific materials. Silica aerogels are fascinating materials because of their peculiar physical properties, such as very low sound velocity [1], large specific surface area [2], low thermal conductivity [3], and fractal structure [4, 5]. The current applications of aerogels include their use as catalysts [8], insulators [3], cosmic dust and space debris captors [9] and glass precursors [7, 10]. These peculiar features are essentially due to the very large pore volume, which can be easily tailored from 0 to 99.5%. This pore volume is controlled by the sol-gel synthesis conditions [6] or sintering [7]. Aerogels are generally described as fractal network [4, 5, 11, 12] in the length scale between 1 and 100 nm. This fractal structure is the result of the aggregation of small particles (1-2 nm) and depends on chemical reaction conditions [5-12]. The aerogel network can be described as an assembly of aggregates (*100 nm). The aggregates can T. Woignier (&) IMEP (Institut Méditerranéen d

Journal of Non-Crystalline Solids, 2004

ABSTRACT Isostatic compression of silica aerogels is known to allow densification of these highly... more ABSTRACT Isostatic compression of silica aerogels is known to allow densification of these highly porous materials. However, at the onset of compression, hydrophobic and consequently slightly reacting aerogels, exhibit a decrease in bulk modulus. This unusual behavior is associated with damage occurring at low pressures which recovers with further density increase. Damage development and healing are analyzed measuring elastic modulus and, for the first time, internal friction as a function of compression. It is proposed that the origin of damage and healing could be associated with the rupture of tenuous links between clusters of dense silica particles at low density levels, and with the creation of new links between the resulting arms and reacting species that are revealed at cluster interface under higher pressure.

Applied Physics A, 2013

ABSTRACT The aim of this work is to demonstrate the sensing ability of reverse-symmetry waveguide... more ABSTRACT The aim of this work is to demonstrate the sensing ability of reverse-symmetry waveguides to investigate adsorption of casein and build-up of poly-L-lysine mediated casein multilayers. A first part of this study is dedicated to the elaboration and characterization of ultra-porous thin films with very low refractive indices by an appropriate sol–gel method. This will form the basis of our planar optical sensors. Optical waveguide light mode spectroscopy is a real-time and sensitive method to study protein adsorption kinetics and lipid bilayers. We used it to test the obtained waveguides for in-situ monitoring of biomolecule adsorption. As a result, significant changes in the incoupling peak position were observed during the layer-by-layer adsorption. Finally, refractive index and thickness of the adsorbed layers were established.

Annals of Emergency Medicine, 1999

The American Journal of Cardiology, 2002

... of age. Nicolas Danchin, MD: Affiliations. Dr. Danchin's address is: Département de Cardi... more ... of age. Nicolas Danchin, MD: Affiliations. Dr. Danchin's address is: Département de Cardiologie, Hôpital Européen Georges Pompidou, 20 rue Leblanc, 75015 Paris, France. ... France. ,; Thibaud Demicheli, MD: Affiliations. Cardiologie ...

American Heart Journal, 1999

A national epidemiological study undertaken in November 1995 recensed the data of 2563 patients a... more A national epidemiological study undertaken in November 1995 recensed the data of 2563 patients admitted to 373 Intensive Care Units for acute myocardial infarction. There were 1827 men and 736 women with an average age of 67 years. Seventeen per cent of patients had left ventricular ejection fration (LVEF) < or = 35%. The mortality rate at 5 days was 7.7%. Clinical heart failure (Killip > 1) was observed in 34.4% of patients. 63% of patients were admitted before the 6th hour. Forty-six per cent of patients underwent early revascularisation by thrombolysis and/or angioplasty. The most widely used drugs in the first 5 days were heparin (96%), aspirin (89%), betablockers (65%), and angiotension converting enzyme inhibitors (46%). The influence of region on the demographical features, morbidity, mortality and therapeutic practice was studied. France was divided into 6 regions. In the Centre, the patients were older, with increased morbidity and mortality compared with the national average. Patients in the North East were similar and had a higher incidence of obesity. In the Ile de France, patients were generally younger with a higher incidence of tobacco consumption and their infarcts were generally less severe. Finally, in the South East, the mortality was particularly low. In multivariate analysis living in this region was good prognostic factor whereas low LVEF (< or = 35%) and age > or = 65 years were poor prognostic factors. This study, for the first time in France, describes the clinical features of myocardial infarction admitted to the Intensive Care Unit with respect to criteria of severity (LVEF, Killip) and region of origin of the patients. Its confirms large regional variations in the severity of acute myocardial infarction.