Effect of amino functional groups on the surface properties and Lewis's acid base parameters of UiO-66(NH) by inverse gas chromatography.

Amino-functionalized metal organic frameworks (MOFs) have attracted much attention for various applications such as carbon dioxide capture, water remediation and catalysis. The focus of this study is to determine the surface and Lewis's acid-base properties of UiO-66(NH) crystals by the inverse gas chromatography (IGC) technique at infinite dilution. The latter was applied to evaluate the dispersive component of the surface energy by using thermal model and several molecular models.

Silica Nanoparticles in Xanthan Gum Solutions: Oil Recovery Efficiency in Core Flooding Tests.

Polymer flooding is one of the enhanced oil recovery (EOR) methods that increase the macroscopic efficiency of the flooding process and enhanced crude oil recovery. In this study, the effect of silica nanoparticles (NP-SiO) in xanthan gum (XG) solutions was investigated through the analysis of efficiency in core flooding tests. First, the viscosity profiles of two polymer solutions, XG biopolymer and synthetic hydrolyzed polyacrylamide (HPAM) polymer, were characterized individually through rheological measurements, with and without salt (NaCl).

Particles' Organization in Direct Oil-in-Water and Reverse Water-in-Oil Pickering Emulsions.

This paper addresses the impact of the particle initial wetting and the viscosity of the oil phase on the structure and rheological properties of direct (Oil/Water) and reverse (Water/Oil) Pickering emulsions. The emulsion structure was investigated via confocal microscopy and static light scattering. The flow and viscoelastic properties were probed by a stress-controlled rheometer.

Effect of Silica Nanoparticles in Xanthan Gum Solutions: Evolution of Viscosity over Time.

The effect of silica nanoparticles (NP-SiO) in xanthan gum (XG) solutions was investigated through the analysis of viscosity profiles. First, hydrocolloid XG solutions and hydrophilic NP-SiO suspensions were characterized individually through rheological measurements, with and without salt (NaCl). Then, nanofluids composed of XG and NP-SiO dispersed in water and brine were studied through two different aging tests.

Interfacial viscoelastic moduli in a weak gel.

Hypothesis: The measurement of interfacial viscoelastic moduli provides information on the ability of surface-active agents to texture the interface. However, the contribution of the bulk rheology cannot be ignored in particular when the continuous phase exhibits a gel-like behavior, even with low modulus.

Experiments: Between 2 and 6 g/L, κ-carrageenan aqueous solutions have no significant activities at interfaces.

Surface thermodynamics and Lewis acid-base properties of metal-organic framework Crystals by Inverse gas chromatography at infinite dilution.

In this study, the surface thermodynamic properties and more particularly, the dispersive component γ of the surface energy of crystals of a Zr-based MOF, UiO-66 (ZrO(OH)(BDC); BDC = benzene 1,4-dicarboxylic acid), the specific interactions, and their acid-base constants were determined by using different molecular models and inverse gas chromatography methods. The determination of γ of the UiO-66 surface was obtained by using several models such as Dorris-Gray and those based on the Fowkes relation by applying the various molecular models giving the surface areas of n-alkanes and polar organic molecules. Six models were used: Kiselev, spherical, geometric, Van der Waals, Redlich-Kwong, and cylindrical models.

Evaluation of the repartition of the particles in Pickering emulsions in relation with their rheological properties.

Hypothesis: The distribution of particles in Pickering emulsions can be estimated through a percolation-type approach coupled to the evolution of their rheological features with the dispersed phase volume fraction ϕ.

Experiments: The rheological behavior of water-in-dodecane Pickering emulsions stabilized with hydrophobic silica nanoparticles is addressed. The emulsions viscosity and elastic modulus are investigated at ϕ varying from 0.

New approach to determine the surface and interface thermodynamic properties of H-β-zeolite/rhodium catalysts by inverse gas chromatography at infinite dilution.

The thermodynamic surface properties and Lewis acid-base constants of H-β-zeolite supported rhodium catalysts were determined by using the inverse gas chromatography technique at infinite dilution. The effect of the temperature and the rhodium percentage supported by zeolite on the acid base properties in Lewis terms of the various catalysts were studied. The dispersive component of the surface energy of Rh/H-β-zeolite was calculated by using both the Dorris and Gray method and the straight-line method.

Comparison of the toxicity of waters containing initially sulfaquinoxaline after photocatalytic treatment by TiO and polyaniline/TiO.

This paper addresses the residual toxicity of waters after photocatalysis treatments The initial waters contain 7 mg L of sulfaquinoxaline (SQX) which is a sulfonamide antibiotic generally recorded inside the water. The contaminated waters are treated by photocatalytic degradation process with bare titania and titania covered with polyaniline (PANI) conducting polymer. The degradation of SQX is conducted at different pH in order to find the optimal condition to obtain SQX concentration relatively equal to zero in the shortest amount of time.

A Facile Approach for Doxorubicine Delivery in Cancer Cells by Responsive and Fluorescent Core/Shell Quantum Dots.

Biocompatible thermoresponsive copolymers based on 2-(2-methoxyethoxy) ethyl methacrylate (MEOMA) and oligo (ethylene glycol) methacrylate (OEGMA) were grown from the surface of ZnO quantum dots (QDs) by surface initiated atom transfer radical polymerization with activators regenerated by electron transfer (SI-ARGET ATRP) in order to design smart and fluorescent core/shell nanosystems to be used toward cancer cells. Tunable lower critical solution temperature (LCST) values were obtained and studied in water and in culture medium. The complete efficiency of the process was demonstrated by the combination of spectroscopic and microscopic studies.

Titania and silica nanoparticles coupled to Chlorin e6 for anti-cancer photodynamic therapy.

In this study, light-sensitive photosensitizers (Chlorin e6, Ce6) were linked to TiO and SiO nanoparticles (NPs) in order to develop new kinds of NP-based drug delivery systems for cancer treatment by PDT. TiO or SiO NPs were modified either by the growth of a polysiloxane layer constituted of two silane reagents ((3-aminopropyl)triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS)) around the core (PEGylated NPs: TiO@4Si-Ce6-PEG, SiO@4Si-Ce6-PEG) or simply modified by APTES alone (APTES-modified NPs: TiO-APTES-Ce6, SiO-APTES-Ce6). Ce6 was covalently attached onto the modified TiO and SiO NPs via an amide bond.

Iron-impregnated zeolite catalyst for efficient removal of micropollutants at very low concentration from Meurthe river.

In this paper, for the first time, faujasite Y zeolite impregnated with iron (III) was employed as a catalyst to remove a real cocktail of micropollutants inside real water samples from the Meurthe river by the means of the heterogeneous photo-Fenton process. The catalyst was prepared by the wet impregnation method using iron (III) nitrate nonahydrate as iron precursor. First, an optimization of the process parameters was conducted using phenol as model macro-pollutant.

The application of titanium dioxide, zinc oxide, fullerene, and graphene nanoparticles in photodynamic therapy.

Nanoparticles (NPs) have been shown to have good ability to improve the targeting and delivery of therapeutics. In the field of photodynamic therapy (PDT), this targeting advantage of NPs could help ensure drug delivery at specific sites. Among the commonly reported NPs for PDT applications, NPs from zinc oxide, titanium dioxide, and fullerene are commonly reported.

Thermo-responsive magnetic FeO@P(MEOMA-OEGMA) NPs and their applications as drug delivery systems.

The unique physical properties of the superparamagnetic nanoparticles (SPIONs) have made them candidates of choice in nanomedicine especially for diagnostic imaging, therapeutic applications and drug delivery based systems. In this study, superparamagnetic FeO NPs were synthesized and functionalized with a biocompatible thermoresponsive copolymer to obtain temperature responsive core/shell NPs. The ultimate goal of this work is to build a drug delivery system able to release anticancer drugs in the physiological temperatures range.

Efficient synthetic access to thermo-responsive core/shell nanoparticles.

Core/shell nanostructures based on silica, fluorescent ZnO quantum dots (QDs) and superparamagnetic FeO nanoparticles (NPs) were prepared and fully characterized by the combination of different techniques and the physical properties of the nanostructures were studied. We demonstrate the efficiency of the atom transfer radical polymerization with activators regenerated by electron transfer process to graft (co-)polymers of different structures and polarity at the surface of metal oxide NPs. The influence of the polymer chain configuration on the optical properties of the ZnO/polymer core/shell QDs was enlightened.

Thermo-responsive and aqueous dispersible ZnO/PNIPAM core/shell nanoparticles.

In this work, we developed a new process to covalently graft a thermoresponsive polymer on the surface of fluorescent nanocrystals in order to synthesize materials that combine both responsive and fluorescent properties. For the first time, poly(N-isopropylacrylamide) (PNIPAM) was grown by activator regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) from ZnO quantum dots (QDs) by surface-initiated polymerization. This process allowed the formation of fluorescent and responsive ZnO/PNIPAM core/shell QDs while only requiring the use of a ppm amount of copper for the synthesis.

Metallo-solid lipid nanoparticles as colloidal tools for meso-macroporous supported catalysts.

Meso-macroporous silica containing iron oxide nanoparticles (15-20 nm) was synthesized by formulating solid lipid nanoparticles and metallosurfactant as both template and metal source. Because of the high active surface area of the catalyst, the material exhibits an excellent performance in a Fenton-like reaction for methylene blue (MB) degradation, even at low amount of iron oxide (5% TOC after 14 h).

Surface-engineered quantum dots for the labeling of hydrophobic microdomains in bacterial biofilms.

Quantum dots (QDs) nanoprobes are emerging as alternatives to small-molecule fluorescent probes in biomedical technology. This paper reports an efficient and rapid method of producing highly dispersed and stable CdSe-core QDs with a hydrophobic gradient. Amphiphilic core/shell CdSe/ZnS QDs were prepared by ligand exchange at the surface of lipophilic CdSe/ZnS QDs using the dihydrolipoic acid (DHLA) dithiol ligand linked to leucine or phenylalanine amino acids.

Experimental contribution to the understanding of the dynamics of spreading of Newtonian fluids: effect of volume, viscosity and surfactant.

The dynamics of drop spreading of glycerol-water mixtures with and without surfactant on hydrophilic glass surfaces has been investigated. The influence of different factors, such as viscosity, drop volume and non-ionic alkyl (8-16) glucoside (Plantacare) surfactant concentration on the number and the nature of the spreading regimes is systematically investigated. More than 25 spreading experiments have been performed in order to obtain clear trends.

Use of surfactants to reduce the driving voltage of switchable optical elements based on electrowetting.

The advantage of using electrowetting as a novel principle for a reflective display has been previously demonstrated. The principle is based on the controlled two-dimensional movement of an oil/water interface across a hydrophobic fluoropolymer insulator. The main objective of this paper is to show experimentally the influence of surfactants on the electro-optic behavior of a single electrowetting pixel.