References of "Cloots, Rudi"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailContribution to the identification of α-, β- and ε-copper phthalocyanine blue pigments in modern artists' paints by X-ray powder diffraction, attenuated total reflectance micro-fourier transform infrared spectroscopy and micro-Raman spectroscopy
Defeyt, Catherine ULg; Vandenabeele, P.; Gilbert, Bernard ULg et al

in Journal of Raman Spectroscopy (2012), 43

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide ... [more ▼]

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide useful technical and chronological information for the study of works of art. Although when a CuPc blue pigment is identified, its crystalline structure often remains unspecified despite the interest for conservation science. In this study, X-ray powder diffraction, attenuated total reflectance micro-Fourier transform infrared spectroscopy and micro-Raman spectroscopy analyses have been carried out on 15 dry pigment samples of CuPc and acrylic, vinylic, alkyd, arabic gum and oil-based artists' paints. By using the polymorphic markers underlined for dry pigments, the CuPc crystalline structure has been successfully identified for most of the analysed artists' paints. However, according to the analytical technique used and the investigated paint sample, the obtained results largely differ. © 2012 John Wiley & Sons, Ltd. [less ▲]

Detailed reference viewed: 30 (9 ULg)
Full Text
Peer Reviewed
See detailNanosphere Lithography and Hydrothermal Growth : How to Increase Surface Area and Control Reversible Wetting Properties of ZnO Nanowire Arrays ?
Colson, Pierre ULg; Schrijnemakers, Audrey ULg; Vertruyen, Bénédicte ULg et al

in Journal of Materials Chemistry (2012), 22(33), 17086-17093

Due to their large surface-area-to-volume ratio as well as their interesting intrinsic optical and electronic properties, ZnO 1D nanostructures are part of the few dominant materials for nanotechnology ... [more ▼]

Due to their large surface-area-to-volume ratio as well as their interesting intrinsic optical and electronic properties, ZnO 1D nanostructures are part of the few dominant materials for nanotechnology. In this article, we compare two different routes of using the nanosphere lithography for the manufacturing of well-aligned, density-controlled ZnO nanowires by low-temperature hydrothermal growth. The first route uses the colloidal mask as a template for the patterned growth of the nanowires, while in the second route, the nanospheres act as a mask to pattern the seed layer. SEM and XRD characterizations are performed on samples manufactured by both routes and evidence patterned well-aligned nanowires with high c-axis texturing in the first synthetic route. Oriented growth is less pronounced in the second route, as well as the ability to adsorb dye. However, for the first route the dye loading measurements reveal that the amount of N-719 adsorbed is higher than on unpatterned ZnO nanowires films, highlighting an increased interface area. Reversible hydrophobicity to superhydrophilicity transition was observed and intelligently controlled by alternation of UV illumination and dark storage. This promising synthetic route opens exciting perspectives for the production of ZnO nanowire arrays with tunable density, wetting properties and enhanced adsorption properties. [less ▲]

Detailed reference viewed: 62 (28 ULg)
Full Text
Peer Reviewed
See detailMicrostructural evolution of a TiO2 mesoporous single layer film under calcination: Effect of stabilization and repeated thermal treatments on the film crystallization and surface area
Dewalque, Jennifer ULg; Cloots, Rudi ULg; Dubreuil, Olivier et al

in Thin Solid Films (2012), 520

This study quantifies the highest perturbation encountered by the first layer of a TiO2 12 layers-mesoporous coating, which is submitted to a multistep calcination process. Besides, we propose an ... [more ▼]

This study quantifies the highest perturbation encountered by the first layer of a TiO2 12 layers-mesoporous coating, which is submitted to a multistep calcination process. Besides, we propose an alternative thermal treatment in order to limit the degradation induced by repeated calcinations. This paper reports and compares the modifications in film thickness, surface area, anatase crystallite size and global crystallinity of films obtained from different thermal treatments. It defines the maximum crystal size compatible with the preservation of the mesoarchitecture initially induced by templating. Differences in microporosity and rate of crystallization are also discussed. [less ▲]

Detailed reference viewed: 61 (19 ULg)
Full Text
Peer Reviewed
See detailStealth macromolecular platforms for the design of MRI blood pool contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Polymer Chemistry (2011), 2(10), 2316-2327

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3 ... [more ▼]

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3+-chelates bearing an azide group was then carried out by the Huisgen 1,3-dipolar cycloaddition (“click”) reaction in mild conditions, leading to macrocontrast agents for MRI applications. The gadolinium complex is hidden in the PEO shell that renders the macrocontrast agents free of any cytotoxicity and stealth to proteins of the immune system. Relaxometry measurements have evidenced an improved relaxivity of the macrocontrast agent compared to ungrafted gadolinium chelate. Moreover, this relaxivity is further enhanced when the spacer length between the Gd3+-chelate and the polymer backbone is shorter, as the result of its decreased tumbling rate. These novel products are therefore promising candidates for MRI applications. [less ▲]

Detailed reference viewed: 54 (17 ULg)
Full Text
Peer Reviewed
See detailConvenient grafting through approach for the preparation of stealth polymeric blood pool magnetic resonance imaging contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2011), 49(17), 3700-3708

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether ... [more ▼]

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether acrylate (PEOMA) with an acrylamide bearing a ligand for gadolinium, followed by the complexation of Gd3+. This convenient and simple grafting through approach leads to macrocontrast agents with a high relaxivity at high frequency that is imparted by the restricted tumbling of the Gd3+ complex caused by its attachment to the polymer backbone. Importantly a very low protein adsorption is also evidenced by the hemolytic CH50 test. It is the result of the poly(ethylene oxide) (PEO) brush that efficiently hides the gadolinium complex and renders it stealth to the proteins of the immune system. Improved contrast and long blood circulating properties are thus expected for these macrocontrast agents. [less ▲]

Detailed reference viewed: 38 (13 ULg)
Full Text
Peer Reviewed
See detailDesign and synthesis of novel DOTA(Gd3+)–polymer conjugates as potential MRI contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Journal of Materials Chemistry (2011), 21(34), 12917-12926

Conventional low molecular weight gadolinium based Magnetic Resonance Imaging (MRI) contrast agents such as Magnevist® are very useful for imaging tissues. However, at the high magnetic fields used in ... [more ▼]

Conventional low molecular weight gadolinium based Magnetic Resonance Imaging (MRI) contrast agents such as Magnevist® are very useful for imaging tissues. However, at the high magnetic fields used in modern MRI equipments, their relaxivity (contrasting efficiency) is rather poor. The grafting of the gadolinium complex onto macromolecules is a way to enhance their relaxivity provided that the rotational motion of the complex is decreased significantly. Here we report the design of novel Gd3+ based MRI contrast agents with improved relaxivity and potential long blood circulation life-time. We investigate the grafting of 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, 1,4,7-tris(1,1-dimethylethyl) ester (DO3AtBu-NH2; a precursor of Gd3+ ligand) onto well-defined functional copolymers bearing activated esters (succinimidyl esters) and poly(ethylene oxide) (PEO) chains required for stealthiness. The tert-butyl groups of grafted DO3AtBu-NH2 are then deprotected by trifluoroacetic acid followed by complexation of Gd3+. Addition of free DOTA at the end of the reaction is necessary to leave the pure and stable water soluble macrocontrast agent. Importantly it shows a relaxivity at high frequencies that is 300% higher than that of the ungrafted gadolinium complex. These novel functional copolymers are therefore promising candidates as macromolecular contrast agents for MRI applications. [less ▲]

Detailed reference viewed: 31 (10 ULg)
Full Text
Peer Reviewed
See detailGenetically engineered polypeptides as a new tool for inorganic nano-particles separation in water based media
Vreuls, Christelle ULg; Genin, Alexis ULg; Zocchi, Germaine ULg et al

in Journal of Materials Chemistry (2011), 21

The present paper relates a method for the separation of an insoluble inorganic powder out of a mixture of several insoluble powders with different chemical compositions, using genetically engineered ... [more ▼]

The present paper relates a method for the separation of an insoluble inorganic powder out of a mixture of several insoluble powders with different chemical compositions, using genetically engineered inorganic binding peptides (GEPI). GEPI are small peptides that recognize and specifically bind an inorganic solid material. This GEPI is anchored to magnetic beads for easy recovery of the powder of interest from the mixture. [less ▲]

Detailed reference viewed: 76 (25 ULg)
Full Text
Peer Reviewed
See detailEvaluation of the pedogenesis effects on the fractionation of metallic trace elements in solid wastes from industrial activities
Pineux, Nathalie ULg; Liénard, Amandine ULg; Cloots, Rudi ULg et al

Poster (2011, July 04)

This work aims at contributing to a better knowledge of the reactivity of metal-bearing phases to evaluate the risks of metal trace elements (MTE) transfers in soil-plant-water system. The high proportion ... [more ▼]

This work aims at contributing to a better knowledge of the reactivity of metal-bearing phases to evaluate the risks of metal trace elements (MTE) transfers in soil-plant-water system. The high proportion of the MTE on this type of sites seems to be mobilized only by particularly aggressive conditions but unstable bearing mineral phases have also been observed in smaller proportions. [less ▲]

Detailed reference viewed: 33 (16 ULg)
Full Text
Peer Reviewed
See detailDense La0.9Sr0.1Ga0.8Mg0.2O2.85 electrolyte for IT-SOFC's: Sintering study and electrochemical characterization
Traina, Karl ULg; Henrist, Catherine ULg; Vertruyen, Bénédicte ULg et al

in Journal of Alloys & Compounds (2011), 509(5), 1493-1500

This paper presents the sintering behaviour of a La0.9Sr0.1Ga0.8Mg0.2O2.85 coral-like microstructure powder. This is prepared by a successive freeze-drying and self-ignition process followed by ... [more ▼]

This paper presents the sintering behaviour of a La0.9Sr0.1Ga0.8Mg0.2O2.85 coral-like microstructure powder. This is prepared by a successive freeze-drying and self-ignition process followed by calcination at 1200 ◦C during 1 h. This synthesis method gives great uniformity of the powder and allows shaping into compacts without requiring a grinding step. The grain size distribution (between 0.5 and 4 m) favours a good sintering behaviour: open porosity disappear at 1400 ◦C and relative densities over 99% can be achieved after 6 h at 1450 ◦C. The same powder can also be sintered into a thin disc of ∼100 mthickness. The characterization of the dense material by impedance spectroscopy shows that the activation energies below and above 600 ◦C are 1.0 eV and 0.7 eV, respectively. The conductivity at 800 ◦C is ∼0.11 S cm−1. Special attention is devoted to the temperature range between 200 ◦C and 400 ◦C, where the intragrain and intergrain contributions can be distinguished. The analysis of the parameters describing the intragrain constant phase element in the equivalent circuit suggests that, above 325 ◦C, the system evolves from a distribution of relaxation time to only one relaxation time. The analysis of the data by the complexes permittivity show that ionic oxide conduction mechanism would occur in two steps. In the first, an oxygen vacancy would be released and, in the second, the migration of the ionic oxide would take place in the material. [less ▲]

Detailed reference viewed: 33 (14 ULg)
Full Text
Peer Reviewed
See detailTiO2 mesoporous thin films studied by Atmospheric Ellipsometric Porosimetry: A case of contamination
Dubreuil, Olivier ULg; Dewalque, Jennifer ULg; Chene, Grégoire ULg et al

in Microporous and Mesoporous Materials (2011), 147

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the ... [more ▼]

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the determination of the porosity of such films. After prolonged exposition to high-vacuum (6×10-6 mbar), the films porosity exhibits a degraded behavior during porosimetric measurements, indicating a vacuum-induced modification. The main effect resulting from such exposition to high-vacuum is a wet- tability modification of the films, resulting in an increase of the hydrophobic character of the TiO2 surface. This evolution induces non-correct results in porosimetric measurements due to the fact that the contact angle parameter needed to calculate the pore size distribution is highly different from the reference films. A surface contamination explains such modifications and a restoration of the films is obtained by using ultraviolet treatment. [less ▲]

Detailed reference viewed: 109 (38 ULg)
Full Text
Peer Reviewed
See detailSpray drying: An alternative synthesis method for polycationic oxide compounds
Rivas-Murias, B.; Fagnard, Jean-François ULg; Vanderbemden, Philippe ULg et al

in Journal Of Physics And Chemistry Of Solids (2011), 72(3), 158-163

Synthesis of polycationic compounds by the spray-drying technique is an interesting alternative in the domain of aqueous precursor synthesis methods. Spray drying yields high quality samples with good ... [more ▼]

Synthesis of polycationic compounds by the spray-drying technique is an interesting alternative in the domain of aqueous precursor synthesis methods. Spray drying yields high quality samples with good reproducibility. The possibility of scaling up for production of large quantities with fast processing time is well established by the commercial availability of powders of various compositions. In this paper, we have discussed the advantages and limitations of this method and demonstrated its interest by synthesizing a few polycationic compounds selected for their attractive properties of thermoelectricity [Bi1.68Ca2Co1.69O8, La(0.95)A(0.05)CoO(3) (A = Ca, Sr, Ba)] or magnetoresistance [La(0.70)A(0.30)MnO(3) (A=Sr, Ba)]. We have confirmed the quality of these samples by reporting their structure, magnetic and transport properties. (C) 2010 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 76 (33 ULg)
Full Text
Peer Reviewed
See detailCharacterization of surface and porous properties of synthetic hybrid lamellar silica
Toussaint, Gilles ULg; Rodriguez, Miguel Angel; Cloots, Rudi ULg et al

in Journal of Non-Crystalline Solids (2011), 357

Synthetic lamellar silica and hybrid lamellar silicas have been prepared by liquid crystal templating, template extraction and silanization. The samples have been characterized by thermogravimetric ... [more ▼]

Synthetic lamellar silica and hybrid lamellar silicas have been prepared by liquid crystal templating, template extraction and silanization. The samples have been characterized by thermogravimetric analysis (TGA), carbon analysis, spectroscopy, X-ray diffraction (XRD) and nitrogen adsorption. The XRD analyses have shown that the lamellar periodic stacking is preserved for all samples. The quantity and type of organic molecules at the silica surface have been evaluated by carbon analysis, TGA and spectroscopy. The covalent grafting of the solvent used for extraction of the initial surfactant has been highlighted by these analyses. The nitrogen adsorption analyses have revealed three categories of pores and two types of samples. The initial lamellar silica exhibits a very low specific surface area and plate-like type of pores. The second type of samples is made up of the hybrid samples and the initial substrate from whom the surfactant has been extracted. These samples show a significantly higher specific surface area with interlamellar spaces corresponding to narrow-slit like mesopores around 4 nm. The nitrogen adsorption data analysis has highlighted the presence of micropores within the silica sheets. The difference of the specific surface is due to pore blocking by the surfactant impeding the access to nitrogen into interlamellar spaces and by the silanes covering the pores once the surface modified. The presence of micro and mesopores combined to a high BET specific surface of 612 m²/g makes these lamellar silicas interesting materials for catalysis applications. [less ▲]

Detailed reference viewed: 35 (9 ULg)
Full Text
Peer Reviewed
See detailOptical properties of thermochromic VO 2 thin films on stainless steel: Experimental and theoretical studies
Lafort, A.; Kebaili, H.; Goumri-Said, S. et al

in Thin Solid Films (2011), 519(10), 3283-3287

Thermochromic films of VO 2 were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO 2 were determined by ellipsometric spectroscopy (0.35-16.5 μm ... [more ▼]

Thermochromic films of VO 2 were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO 2 were determined by ellipsometric spectroscopy (0.35-16.5 μm) for different film thicknesses. Optical simulations were performed to model the spectral reflectance of the film/substrate system for a film thickness of 100 nm and 200 nm and to monitor the optical contrast of the thermochromic layers by comparing the spectral reflectance at 25 °C and 100 °C. The good agreement observed between experimental and theoretical spectra demonstrates the adequacy of the model for predicting the optical properties of the samples. © 2010 Elsevier B.V. All rights Reserved. [less ▲]

Detailed reference viewed: 21 (6 ULg)
Full Text
Peer Reviewed
See detailStudy of the effect of a silver nanoparticle seeding layer on the crystallisation temperature, photoinduced hydrophylic and catalytic properties of TiO 2 thin films deposited on glass by magnetron sputtering
Limage, H.; Tichelaar, F. D.; Closset, Raphaël ULg et al

in Surface & Coatings Technology (2011), 205(13-14), 3774-3778

The optimization of the photocatalytic activity and hydrophilic conversion of TiO 2 is an active research area in the field of self-cleaning materials and energy storage/conversion. One major focus is the ... [more ▼]

The optimization of the photocatalytic activity and hydrophilic conversion of TiO 2 is an active research area in the field of self-cleaning materials and energy storage/conversion. One major focus is the crystalline phase of TiO 2, known to be the most efficient of the anatase structures. Another issue is the decoration of TiO 2 with noble metals, which act as charge carrier traps for electrons. The latter hinders or reduces the electron-hole recombination rate and often leads to a more efficient photocatalytic activity. In this paper, we describe how an interlayer consisting of 3-4nm silver nanoparticles (Ag-NPs) promotes TiO 2 anatase crystallisation and has a positive effect on the photoinduced catalytic and hydrophylic properties of TiO 2 thin films. Ag-NPs and TiO 2 were deposited by magnetron sputtering in the same reactor in a two-step process: a) condensation of Ag-NPs produced in the gas phase thanks to a high-pressure discharge, and b) conventional TiO 2 magnetron deposition in oxide mode. Four temperatures from RT to 288°C were investigated and film thickness was 80nm. Particle size and film structure were determined by TEM, HRTEM and XRD. Photocatalytic activities of the samples were tracked by the evaluation of the surface hydrophilicity after UV illumination and 24. hours post-illumination, and by UV-induced palmitic acid degradation. © 2011. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Full Text
Peer Reviewed
See detailMicrowave properties of DyBCO monodomain in the mixed state and comparison with other RE-BCO systems
Pompeo, N.; Rogai, R.; Ausloos, Marcel ULg et al

in Physica C: Superconductivity and its Applications (2011), 471(21-22), 854-858

We report on microwave measurements on DyBa 2Cu 3O 7-δ monodomains grown by the top-seeded melt-textured technique. We measured the field increase of the surface resistance R s(H) in the a-b plane at 48.3 ... [more ▼]

We report on microwave measurements on DyBa 2Cu 3O 7-δ monodomains grown by the top-seeded melt-textured technique. We measured the field increase of the surface resistance R s(H) in the a-b plane at 48.3 GHz. Measurements were performed at fixed temperatures in the range 70 K-T c with a static magnetic field μ 0H < 0.8 T parallel to the c-axis. Low field steep increase of the dissipation, typical signature of the presence of weak links, is absent, thus indicating the single-domain behavior of the sample under study. The magnetic field dependence of R s(H) is ascribed to the dissipation caused by vortex motion. The analysis of X s(H) points to a free-flow regime, thus allowing to obtain the vortex viscosity as a function of temperature. We compare the results with those obtained on RE-BCO systems. In particular, we consider strongly pinned films of YBa 2Cu 3O 7-δ with nanometric BaZrO 3 inclusions. © 2011 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 9 (2 ULg)
Full Text
Peer Reviewed
See detailEffect of non-ionic surfactant and acidity on chitosan nanofibers with different molecular weights
Ziani, Khalid; Henrist, Catherine ULg; Jerome, Christine et al

in Carbohydrate Polymers (2011), 83(2), 470-476

Detailed reference viewed: 57 (8 ULg)