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Hypothesis Newtonian liquids, usually used as base oil lubricants, exhibit low viscosity under extreme thermal conditions, needed for the functioning of wind turbines. This is directly affecting the colloidal stability and the tribological properties of the formulations containing additives, such as MoS2. Here, it was hypothesized that the surface hydrophobization of MoS2 particles will allow for an increased colloidal stability of the resulting formulations, for temperatures as high as 80 °C. Experiments The antifriction properties and the thermal stability of the designed formulations were determined on submicron MoS2 particles dispersed in poly-α-olefins (PAO) base oils of different dynamic viscosities (from 32 to 1650 mPa·s at 25 °C). The submicron particles of MoS2 (300–500 nm in diameter) were synthesised by a simple one-pot solvothermal method under mild conditions. The resulting particles were hydrophobized in situ in PAO base oils using alkyltrichlorosilane grafting agents with two chain lengths (C8 and C18). Findings The covalent grafting of alkylsilanes through Mo-O-Si bonds was confirmed by DFT calculations and FT-IR measurements. Turbiscan optical analysis revealed that thermal and colloidal stabilities can be significantly improved depending on oil viscosity and chain length of the grafting agent. The formulations in the PAO65 oil remained highly stable (TSI

The upgrading of lignin-derived bio-oils involves a HydroDeOxygenation (HDO) reaction through either the Hydrogenation (Hyd) or the Direct DeOxygenation (DDO) route, the latter limiting hydrogen consumption. Herein, dispersion-corrected DFT has been used to evaluate the adsorption behavior of phenol (as a representative model of bio-oils) and two by-products (water and CO) over various crystalline and amorphous silica surfaces to evaluate their potential selectivity (DDO/Hyd) and efficiency (low inhibiting effect) for HDO processing. Phenol can adsorb through three modes, flat π-interaction, flat O-interaction or perpendicular O-interaction. All crystalline surfaces show a preference for the flat π-interaction, which is expected to promote the Hyd route. Over amorphous surfaces the flat O-interaction dominates, and a very specific and strong interaction (around −120 kJ/mol) was found on SiO2-3.3 and SiO2-2.0 surfaces where the phenol molecule loses its aromaticity, which is very promising for its degradation under catalytic conditions. In addition, this makes those surfaces very efficient to adsorb selectively phenol in presence of water and CO. Remarkably, on all silica surfaces, the interaction energy of CO is nearly negligible, which makes them more attractive for HDO process compared to sulfide catalysts with respect to the inhibiting effect criteria.

International audience; The use of MoS ⁠ 2 nanoparticles as additive to lubricating oils is restricted by their low stability in oily media, which limits their use despite the enormous benefits associated with their intrinsic properties in terms of reduction of friction and wear coefficients. In this context, we investigated the effect of morphologies (platelets vs spheres) and surface functionalization of nanoparticles on the stability of their suspensions in poly-α-olefins (PAO) with various viscosities, which are base oils used in wind turbines. The particles were characterized by XRD, FTIR, scanning electron microscopy, atomic force microscopy and dynamic light scattering, and the stability of the resultant formulations was followed by optical (non-contact) measurements. It was found that the dispersions had similar stability despite the larger size of platelet-like particles compared to spherical ones (1-5 μm vs 600-800 nm). The dispersibility could be increased through grafting of alkylsilane on the surface defects (the longer the alkyl chain, the more stable the formulation) and with the increase of the oil kinematic viscosity (from 34 to 1705 cps at 25 °C).

Hollow carbon spheres (HCSs) were prepared from sugar alcohols encapsulated in UV-cured polymer which were hydrothermally treated in solutions of carbon precursors and carbonised at different temperatures in the presence or absence of graphitisation catalysts (Fe(III) and Ni(II)). The resultant HCSs were then spread at the surface of salt water and submitted to a solar simulator in a special ventilated chamber. The presence of HCSs floating at the surface of water was shown to increase significantly the evaporation rate compared to an HCS-free reference. The effect of carbon precursor, pyrolysis temperature, size and presence of metal was investigated and discussed. The best performances were obtained with nickel-loaded HCSs treated at 1500 °C, leading to a water evaporation rate increased by 70% with respect to the reference. These performances were discussed in terms of floatability, the latter being related to wettability, composition and apparent density of the HCSs. A model was developed for separating the contributions of floatability and thermal conductivity, definitely demonstrating that the former was the key parameter explaining the performances of floating HCSs for evaporating water submitted to a radiant heat flow.

The catalytic hydrodeoxygenation (HDO) of lignin is an important route to produce green aromatics. Herein we study the adsorption of key phenolic molecules (phenol, catechol, guaiacol, anisole) over various metallic nanoparticles (NP) (Ni, Cu, Co, Fe) supported over amorphous silica, by the periodic spin polarized density functional theory (DFT). CO and water are potential inhibiting molecules present in the lignin pyrolysis gas. Therefore their competing adsorption is also studied in details. Our calculations show that the oxygenated compounds have a stronger interaction at the interface between the NP cluster and the silica for all the studied metals. By comparing the resulting adsorption energies, we found that the Ni13@silica catalyst is the most attractive one for oxygenated molecules. The most stable configuration is a phenol adsorption at the interface through the OH group with the silica surface and the aromatic ring with the transition metal cluster. In addition, we show that the adsorption of the oxygenated compounds is not impacted by the presence of inhibiting molecules on Fe13@silica, Co13@silica and Ni13@silica catalysts. This type of DFT investigation appears to be useful to suggest suitable formulations for an optimal HDO of lignin.

According to the US Food and Drug Administration and the European Food Safety Authority, amorphous forms of silica and silicates are generally recognized to be safe as oral delivery ingredients in amounts up to 1500mg per day. Silica is used in the formulation of solid dosage forms, e.g. tablets, as glidant or lubricant. The synthesis of silica-based materials depends on the payload nature, drug, macromolecule or cell, and on the target release (active or passive). In the literature, most of the examples deal with the encapsulation of drugs in mesoporous silica nanoparticles. Still to date limited reports concerning the delivery of encapsulated macromolecules and cells have been reported in the field of oral delivery, despite the multiple promising examples demonstrating the compatibility of the sol-gel route with biological entities, likewise the interest of silica as an oral carrier. Silica diatoms appear as an elegant, cost-effective and promising alternative to synthetic sol-gel-based materials. This review reports the latest advances silica-based systems and discusses the potential benefits and drawbacks of using silica for oral delivery of drugs, macromolecules or cells.

International audience; Due to their properties nano-emulsions are excellent candidates to be used as imprints to create a macropore network. In this study nano-emulsions have been formulated from the Remcopal 4/decane/water system and mineralized by a dual templating mechanism in the presence of Pluronic P123 micelles. After removing the organic matter, macro-mesostructured silica materials are obtained. Small angle X-ray scattering patterns of the materials and transmission electronic microscopy experiments show that the mesoporous network (mesopore size around 9 nm) adopts a hexagonal arrangement. Macropores have been characterized by transmission electron microscopy, scanning electron microscopy and mercury porosity. As determined by mercury porosimetry, the size of the macropores imprinted by the nano-emulsions is of about 240 nm. A second macroporosity is also detected in the micrometer range and could be related to the further fusion of nano-emulsions during the hydrothermal process and to interparticular porosity. To better address the formation mechanism of the hierarchical structure of the silica material, the stability of nano-emulsions in the presence of methanol, P123 and both of them has been investigated. We have also evidenced the dual role played by the Pluronic micelles. They do not only induce the mesopore network through the cooperative templating mechanism, but their presence also avoids the total destructuration of the nano-emulsion by methanol, released during the hydrolysis of the silica precursor.

The tautomerism of curcumin (CUR) in aqueous solution was investigated in the presence of silver nanoparticles (AgNPs) in the temperature range 294−314 K. The kinetic data indicate that the conversion of the keto-enol into the diketo form is associated to higher rate constants in comparison to those obtained in pure water. Moreover, nonlinear Arrhenius behavior was observed in the investigated temperature range. The effects of CUR on the AgNPs were determined by zeta potential and dynamic light scattering measurements and supported by spectroscopic analysis suggesting that interactions with metal surface occur preserving nanoparticles from self-aggregation in the investigated conditions. The results reported herein contribute to enhance the kinetics of CUR tautomerism in aqueous media.

The interfacial behavior of curcumin, a model anti-inflammatory drug was studied upon interaction with cetyl palmitate and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine. Cetyl palmitate finds applications for topical delivery in nanostructured lipid carriers, while the phosphatidylcholine was used both as a component of the carrier and as a model membrane lipid. Here, surface pressure, thermodynamics, Brewster angle microscopy, molecular dynamics and polarization modulation infrared reflection-absorption spectroscopy were used to better our understanding of the interaction between the components of the delivery systems and, on the other hand, of their interaction with biological membranes. Moreover, thermodynamics was used to analyze the effect of curcumin on the lipid systems and, in particular, on the model membranes. The results obtained indicate that mixtures of curcumin and cetyl palmitate form Langmuir films, while none of the two pure components does. This effect was interpreted in terms of formation of a complex between curcumin and the hydrophobic, water insoluble cetyl palmitate. The hydrophilic-hydrophobic balance of the complex allows its penetration into the monolayer and mixing with the phospholipid phase. This finding may be of interest for further design of phytolipids for drug delivery applications.

The authors regret that the printed version of the above article contained some errors in the value of the lower bound of thermal conductivity considered and discussed in section 3.5. The correct and final version follows. The authors would like to apologise for any inconvenience caused. The penultimate paragraph of section 3.5 should read: ""This range, which is already unrealistically broad, was widened further to 0.02-10 W m−1 K−1, and those extreme values were tested. The results are shown in Fig. 14. It can be seen that the impact of the thermal conductivity is quite low since a change of less than 10% was obtained. This finding definitely suggests that the effect observed by Zhou et al. [4] was not attributable to some differences of thermal conductivity but to another physical properties of their HCSs, since the authors could only multiply the conductivity by a factor 1.23 (against 500 in the simulation) by changing the composition of their materials."" The new Fig. 14 is thus the following (only the legends written inside the plots are modified, not the plots themselves). Fig. 14. Calculated change of evaporation rate as a function of the position of the HCS, for two extreme values of its thermal conductivity, l (""lam"" on the plots). (b) is a zoom of (a) in the range of positions where the water evaporation changes the most. (A colour version of this figure can be viewed online.)

International audience; A new catanionic system associating amphiphilic carnosine (beta AlaHisC8) and lauric acid forms supramolecular hydrogel at a very low concentration. This gel was investigated and we checked the validity of the concept of hydrogel utilization to reduce boron leachability and to develop new wood protection treatments. Impregnation with 5% aqueous borax solution (w/w) and 0.3% gelator agent (w/w) fosters improvement in the resistance of Scots pine sapwood subjected to water leaching toward the brown-rot fungus Poria placenta, while samples treated with 5% aqueous borax solution were partially degraded by the fungus. These results clearly indicate the effectiveness of hydrogel to retain boron in wood.

Fluorinated compounds are not only more hydrophobic than their hydrogenated counterparts but also oleophobic. This makes them interesting for biomedical applications. They form a large variety of supramolecular architectures and, if appropriately designed, they spontaneously form vesicles. Herein we report the synthesis of novel monocatenar fluorinated surfactant, named F 9 NH(EO) 2 NH 2 , its use as ss DNA vector with potential applications in gene delivery or RNA interference. The molecular structure of the amphiphilic compound was designed in three parts: (i) a fluorinated hydrophobic tag responsible of self-assembling, (ii) a flexible and hydrophilic ethylenoxide moiety as polar head and (iii) a protonated at physiological pH primary amine responsible of binding. Surface tension, dynamic light scattering (DLS) measurements, and TEM studies showed that the monocatenar surfactant F 9 NH(EO) 2 NH 2 spontaneously self-assembles into vesicles. This represents another example in addition to the few existing in the literature and it highlights the unique properties of the fluorinated tail. Interactions between ss DNA and cationic monocharged F 9 NH(EO) 2 NH 2 were probed by static light scattering (SLS), fluorescence and circular dichroism (CD). F 9 NH(EO) 2 NH 2 was found to exclude ethidium bromide (EB) from ss DNA/EB complex, and this process was dependent on the ss DNA concentration and on the charge ratio surfactant to ss DNA. CD spectra showed that by increasing the surfactant concentration, ss DNA undergoes a continuous conformational transition from native B-form to a more ordered phase (Z + /Z − ≤ 3) and then to a less ordered phase (Z + /Z − ≥ 4), which confirmed the results obtained by fluorimetry and SLS measurements. Cell viability studies reveled that monocatenar fluorinated surfactant F 9 NH(EO) 2 NH 2 is not toxic for human cells (MRC-5) below 40 μM.

A simple route to fluoroalkylated functionalized secondary amines is proposed by the treatment of 2-perfluoroalkylprop-2-enoic acids with various primary amines. Two of these compounds were obtained from oxyethylenic diamine and present an amphiphilic structure. These compounds exhibit an excellent surface activity since they are lowering the surface tension to 18–20 mN/m and this, at very low concentrations (around 10 −5 M). DLS measurements and TEM studies show an original behavior of the monocatenar fluorinated surfactants 5n and 5o , which are able to spontaneously self-assembles into vesicles, and therefore it makes them suitable candidates as carriers in drug or gene delivery systems.

The synthesis of novel histidine-based surfactants and their self-assembling properties into anisotropic microscopic and macroscopic spaces are reported. Below pH 8, surfactant molecules self-assemble into micelles whereas hydrogelation occurs above pH 8 even at very low concentrations (0.3%w/v). Structure, size, and morphology of the fiber-like lamellar aggregates were determined by SAXS and WAXS measurements, polarized optical microscopy, transmission and scanning electron microscopy, and linear and circular dichroism.

The membrane selectivity may be induced either by carrier molecules or by transmembrane channels. From the mechanistic point of view, we use carriers which self-assemble in functional aggregates which would present combined (hybrid) intermediate features between the former carrier-monomers and the resulted channel-forming superstructures. Thus, we therefore studied the membrane transport properties in hybrid dense solid or in mesoporous membranes of such supramolecular organic–inorganic hybrid systems resulted by the dynamic self-assembly of the hydrogen-bonded urea-crown ethers, aromatic aminoacids and nucleosides. This review presents a survey of different methods and processes which can be used for the generation of hybrid supramolecular membranes. Then, basic working principles of molecular recognition-type and self-organized membranes are provided in order to better understand requirements in material design for the generation of functional ionic-conduction pathways. Finally, these systems have been employed successfully to design new dynamic-site complexant membranes immobilized in a mesoporous hybrid nanospace.

The synthesis and physico-chemical investigation of a cationic, water-soluble surfactant of formula C8F17CH2CH(OH)CH2NH2+CH2CH(OH)CH2OH, Lac− (Lac = lactobionate), bearing a single-fluorocarbon tail and the lactobionate moiety as a counterion is reported. It forms spontaneously in water bilayer vesicles with a polydisperse distribution in size. This behavior could be attributed to a possible asymmetry of the bilayers due to an excess of the counterion outside the vesicles and possible stabilization by hydrogen bond interactions between the aminoalcohol polar heads of the cationic surfactant inside the vesicle.