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Although transition metal sulfides have prodigious potential for use as electrode materials because of their low electronegativities, their large volume changes inhibit broad application. Moreover, there is only limited knowledge of the ageing processes of these materials at the nanoscale. Herein, nano-C/FeS2 materials were prepared via one-pot syntheses from green biodegradable carbon precursors, followed by activation and sulfidation. The increased activation/sulfidation time led to an increase in the size of the nanoparticles (7 to 17 nm) and their aggregation, as well as in an increase in the specific surface area. The materials were then used as electrodes in 2-electrode symmetric supercapacitors with 2 M KOH. The activation process resulted in improved capacitance (60 F g−1 at 0.1 A g−1) and rate capability (36%) depending on the composite porosity, conductivity, and size of the FeS2 particles. The ageing of the FeS2 nanoparticles was investigated under air, and a progressive transformation of the nano-FeS2 into hydrated iron hydroxy sulfate with a significant morphological modification was observed, resulting in drastic decreases in the capacitance (70%) and retention. In contrast, the ageing of nano-FeS2 during cycling led to the formation of a supplementary iron oxyhydroxide phase, which contributed to the enhanced capacitance (57%) and long-term cycling (132% up to 10,000 cycles) of the device. [ABSTRACT FROM AUTHOR]

The plasma polymerization of hexamethyldisiloxane (HMDSO) leads to the environmentally friendly fabrication of water-repellent coatings through a vapor-phase surface functionalization process using alternatives to the controversial perfluoroacrylate precursors. However, the durability of these coatings is their Achilles' heel, which requires an in-depth study of the relationship between the structure and properties of these thin films in order to propose concrete solutions for the fabrication of fluorine-free water-repellent textiles. In this context, HMDSO plasma polymers have been deposited on cotton fabrics in an original reactor that allows easy tuning of temporal and spatial parameters of the glow discharge. The functionalized fabrics were characterized to gain insights into the chemical composition of the coatings, their morphology and, above all, their adhesion properties. Interestingly, the results after washing tests revealed a significant dependence of the durability of the superhydrophobic property on the elastic modulus of the deposited polymer. The formation of some radicals at the substrate–thin film interface in the early stages of deposition also correlates with some results. These relationships between the operating conditions of the plasma polymerization, the interfacial properties and the performances of the functionalized fabrics, but also the characterization methodology developed in this work, can undoubtedly serve the engineering of water-repellent fluorine-free coatings on fabrics with optimal durability. [ABSTRACT FROM AUTHOR]

C‐rich graphitic carbonitride materials (CNx) with a large range of compositions have been prepared thanks to the self‐assembly, in different ratios, of melamine (M) and a panel of polycarboxylic acids (A) such as oxalic, tartaric and citric acid. The thermal conversion of the formed adducts (MAy), led to CNx phases, with x ranging from 0.66 to 1.4 (x=1.33 for g‐C3N4 for comparison). The properties of these materials were examined by different techniques (XRD, Raman spectroscopy, TEM, TGA, XPS and DRIFT). It appears that the increase in the C content is associated with the disappearance of the long‐range order of heptazine units and an increase in the sub‐nanometer carbon‐rich cluster size within the graphitic g‐C3N4 structure. This trend is followed by a significant increase in the interlayer spacing and a lower proportion of N=C−N bonds compared to C=C bonds. The thermal stability under an inert atmosphere of these phases and their UV‐Visible absorbance properties were also investigated. [ABSTRACT FROM AUTHOR]

The properties of the final product resulting from plasma polymerization strongly depend on the operating conditions and they impact the final application of the plasma polymer coating. Low‐pressure pulsed plasma polymerization of maleic anhydride was investigated at two different positions in relation to the glow discharge in a 1‐m‐long tubular reactor. Interestingly, competition was observed in the deposition of maleic anhydride plasma polymer in the form of a smooth thin film versus that in the form of nanoparticles. The possibility of a spatiotemporal control of plasma polymerization enabled the deposition of a plasma coating with tunable morphological properties depending on the sample position from the glow discharge and on the plasma pulse parameters (on‐time and off‐time). [ABSTRACT FROM AUTHOR]

The impact of surface chemistry on the morphogenesis of maleic anhydride plasma polymer is investigated on silicon wafers with very well‐controlled surface chemistries (i.e., native oxide, hydroxyl‐rich, and alkyl‐rich). A particular attention is paid to characterize the early stages of growth. Two different morphologies of polymer films are obtained, depending on the hydrophilic or hydrophobic nature of the substrate surface, even though the chemical composition is very similar. Homogeneous and dense polymer films are formed on hydrophilic substrates due to the strong affinity of plasma species toward the surface. Elongated nanostructures resulting in a less dense polymer film grow on the hydrophobic surface, which are assumed to be the result of the low affinity of plasma species. [ABSTRACT FROM AUTHOR]

Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high‐performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self‐propagating high‐temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m2/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant‐based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated. [ABSTRACT FROM AUTHOR]

Cobalt (II) acetate is mixed with zinc methacrylate (ZnMAA) to form a photopatternable Co-doped zinc oxide precursor. By using deep-UV (DUV) interference lithography, Co-doped ZnMAA precursor can be patterned as negative tone resist and transformed into ferromagnetic Co:ZnO films after thermal treatment. Moreover, Co:ZnO patterns as small as 300 nm line-width can be easily obtained. To have an in-depth understanding to the effect of DUV-patterning process as well as thermal annealing on Co:ZnO films derived from Co-doped ZnMAA precursor, optical, magnetic, and electrical characterizations are performed on Co:ZnO films prepared in different conditions. For the Co:ZnO film prepared without DUV-patterning, large zero-field-cooling (ZFC)-field-cooling (FC) irreversibility appears in superconducting quantum interference device measurements after vacuum annealing, indicating that Co clusters have formed inside the film. On the other hand, no ZFC-FC bifurcation can be observed for the DUV-patterned Co:ZnO film after the vacuum annealing, suggesting that the uniformity of Co ion distribution inside ZnO lattice is improved by DUV-patterning. [ABSTRACT FROM AUTHOR]

In the present work, copper species were incorporated in SBA-15 organized mesoporous silica (“OMS”) through wet impregnation of copper nitrate and the corresponding material was evaluated as SO 2 adsorbent. The calcination under a high flow of synthetic air leads to the formation of highly dispersed copper species in strong interaction with the support (Cu 2 + O Si). Indeed, the characterization of this material by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), do not indicate the presence of crystalline CuO. A comprehensive X-ray Photoelectron Spectroscopy (XPS) study allowed the identification of the active species in SO x trapping and underlined the importance of a thermal pretreatment on the performances of the adsorbent in SO x trapping. It reveals that a pretreatment at 600 °C leads to the formation of active Cu + species in higher amount ([Cu + ] = 79.0%) than at 400 °C ([Cu + ] = 37.6%), which strongly increases the adsorbent efficiency. These species were found to be stable in the presence of [O 2 ] = 10% (balance nitrogen) at 400 °C but unstable at ambient atmosphere at room temperature (presence of water). The treatment under SO 2 at 400 °C leads to the reoxidation of the Cu + species into Cu 2 + ones, which are partially sulfated (formation of CuSO 4 ). Additionally, the sulfation step causes the sintering of a part of the Cu 2 + O Si species into CuO. A reaction scheme was proposed according to which, in a first step Cu + species catalyze the SO 2 oxidation to SO 3 . In the second step, Cu(I) is reoxidized into Cu(II) as CuSO 4 . [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the effect of interfacial covalent bonds on the adhesive behavior of an elastomer, a crosslinked polydimethylsiloxane, and a glass substrate. These covalent bonds were created by applying to both materials an appropriate surface treatment by means of plasma polymerization. Adhesion measurements were carried out by analyzing the contact area between a rubber hemisphere and a flat rigid glass plate. The contact was forced under a given compressive loading for different times tc, then the load was removed and the fracture propagation at the interface was recorded as a function of relaxation time tr. Finally, adhesion energies were also determined by means of a probe test using a tensile testing machine. [ABSTRACT FROM PUBLISHER]

Functional ultrafiltration membranes can be used for water decontamination. Here, we investigate the use of plasma polymerization to modify polymeric membranes with poly(allylamine) in order to filtrate aqueous solutions contaminated with Ni(II) ions. A preliminary study is performed to control growth kinetics of polymer thin films with respect to the energy provided to the precursor during deposition. Filtration experiments then enable to quantify the efficiency of the different functional coatings as for their retention of Ni(II) ions and to identify the optimal characteristics of the polymer thin films. Retention rate as high as 96% can be achieved by this single‐step functionalization process, which is very competitive compared to conventional multi‐step wet chemical functionalization techniques. Ultrafiltration membranes are functionalized with poly(allylamine) by plasma polymerization for water decontamination. By controlling growth kinetics and physico‐chemical properties of plasma coatings, retention rate of Ni(II) ions as high as 96% can be achieved by this single‐step functionalization process, which is very competitive compared to conventional multi‐step wet chemical techniques. [ABSTRACT FROM AUTHOR]

Coatings have been deposited from acrylates and methacrylates mixtures by means of an aerosol assisted atmospheric plasma process. The reference coating precursor is dodecyl acrylate (DOCA). In order to improve the coatings mechanical properties, one diacrylate and one dimethacrylate are added to DOCA in the precursor mixture. It is expected that they act as cross‐linking agents, thus modifying the coatings macromolecular structure and improving the coating mechanical properties. The influence of cross‐linkers concentration on the coatings properties is investigated. An improvement of coatings scratch resistance when the concentration of cross‐linkers increases in the mixture is observed, but the effect on coatings structure is different between the diacrylate and the dimethacrylate. This work introduces new insights in the frame of plasma coatings deposition by investigating the reinforcement of plasma polymers when cross‐linkers are added to the precursors mixture. An improvement of coatings scratch resistance when the concentration of cross‐linkers increases in the mixture is observed, but the effect on coatings structure is different between the two crosslinkers under study. [ABSTRACT FROM AUTHOR]

Abstract: Junctions between aluminium substrates and ethylene-co-propylene-co-diene terpolymer (EPDM) have been strengthened by depositing alkene functionalized plasma polymers on the aluminium side. The double bonds in the plasma polymer layer were able to covalently bond to the EPDM during the crosslinking step with peroxide. Variations in the peel strength were observed by varying of the plasma duty cycle during plasma polymer deposition. The higher peel strength was obtained with low duty cycles. Analysis of the failure after peel tests showed a cohesive rupture in the EPDM substrate. The differences were explained by analysing the respective concentration of alkene groups in the plasma polymer layer. [Copyright &y& Elsevier]