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This article reports on the synthesis of an innovative smart polymer, P5‐QPDMAEMA, opportunely developed with the aim of combining the responsiveness of PDMAEMA polymer and the host‐guest properties of covalently linked pillar[5]arenes. Thanks to a traditional Non‐Induced Phase Separation (NIPS) process performed at various coagulation pH, the blending of P5‐QPDMAEMA with polyethersulfone gave rise to the formation of functional beads for the removal of organic dyes in water. Adsorption tests are carried out on all the produced blend‐based beads by employing two representative dyes, the cationic methylene blue (MB), and the anionic methyl orange (MO). In particular, the P5‐QPDMAEMA based beads, prepared at acidic pH, featured the best MO removal rate (i. e., 91.3 % after 150 minutes starting from a 20 mg ⋅ L−1 solution) and a high selectivity towards the removal of the selected anionic dye. Based on the adsorption kinetics and isotherm calculations, the pseudo‐first order and Freundlich models were shown to be the most suitable to describe the MO adsorption behavior, achieving a maximum adsorption capacity of 21.54 mg ⋅ g−1. Furthermore, zwitterionic beads are obtained by a post‐functionalization of the PDMAEMA and the P5‐QPDMAEMA based beads, to test their removal capability towards both anionic and cationic dyes, as shown. [ABSTRACT FROM AUTHOR]

ZnO thin films with a thickness of 300 nm were deposited on Si and Al2O3 substrates using an electron beam evaporation technique with the aim of testing them as low cost and low power consumption gas sensors for ozone (O3). Scanning electron microscopy and atomic force microscopy were used to characterize the film surface morphology and quantify the roughness and grain size, recognized as the primary parameters influencing the gas sensitivity due to their direct impact on the effective sensing area. The crystalline structure and elemental composition were studied through Raman spectroscopy and X-ray photoelectron spectroscopy. Gas tests were conducted at room temperature and zero-bias voltage to assess the sensitivity and response as a function of time of the films to O3 pollutant. The results indicate that the films deposited on Al2O3 exhibit promising characteristics, such as high sensitivity and a very short response time (<2 s) to the gas concentration. Additionally, it was observed that the films display pronounced degradation effects after a significant exposure to O3. [ABSTRACT FROM AUTHOR]

Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work function of photovoltaic (PV) anodes in hybrid thermionic devices for the conversion of thermal‐to‐electrical energy. Because PV anodes integrated in thermionic converters can operate at temperatures higher than room temperature, in this study, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the temperature dependence up to 300°C of the chemical and physical properties of BaFx thin‐films, deposited on gallium arsenide and silicon, that represent possible candidates for PV anodes. A correlation between chemical composition and work function reduction by 0.5 ± 0.1 eV for the thin films on both GaAs and Si has been found as a function of temperature from room temperature to 300°C. According to XPS analyses, this effect can be ascribable to the thermal desorption of the first contaminated layers of BaFx coatings. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are widely employed in commercial dental devices. Because the surface morphology and chemical composition of Ti‐based dental implants play a relevant role in osseointegration, three different commercial threaded implants have been investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS). The Implants A and C were made of pure Ti whereas the Implant B was made of Ti6Al4V alloy. Obtained results evidenced the common features and differences due to specific process parameters used in the treatments of mordanting and sandblasting for surface roughening. Implant A exhibits a uniform surface covered by very small dimples of about 1–2 μm. The surface of Implant B is not homogeneous: The thread tops present an irregular morphology (dimples size >10 μm) while finer dimples (about 1 μm) are observed along the thread flanks and valleys. Implant C shows an irregular morphology with dimples of different sizes and shapes distributed on thread tops, flanks, and valleys. XPS analyses revealed the presence of metal oxides: TiO2 in all the implants; Al2O3 and V2O5 only in the implant B. Moreover, these results demonstrated that Mg2SiO4 is present on the surface of Implant A, probably due to a specific preparation process. Obtained results have been discussed on the basis of the factors promoting the osseointegration. [ABSTRACT FROM AUTHOR]

Thin Al foils are promising materials for applications in devices of microelectromechanical systems (MEMS). In this work, three foils of high purity (5N) Al with different thickness (10, 50, and 125 μm) were analyzed by means of X‐ray photoelectron spectroscopy (XPS), before and after annealing (720 K for 30 min). XPS surface analysis and depth profiling of chemical composition were performed to investigate the distribution of Al oxide. Electron energy loss spectroscopy (EELS) measurements were also carried out in order to identify the plasmon losses and chemical state of Al. The loss peaks in the 5N‐Al thin foils were compared with those of an Al foil of commercial purity (99.95 wt%). The thickness of the oxide layer on the sample surface of all the samples is not constant and oxide is thicker in the samples of high purity than in those of commercial quality. Moreover, the thinnest foils of 5N‐Al (10 μm) exhibit the thinnest oxide layer. These findings have been discussed by considering the size effect, that is, mechanical properties of thin foils are improving as the thickness decreases. The complex morphology of the metal‐oxide interface may contribute to enhance the mechanical performances of Al foils with a thickness below ~50 μm, because the free dislocations pile up against the interface which represents an obstacle for their motion hindering plastic deformation. Obtained results suggest that Al foils to be used in MEMS devices should be of high purity and annealed to get a surface completely covered by the oxide layer. [ABSTRACT FROM AUTHOR]

Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) measurements were performed on the films deposited by electron-beam evaporation with different nominal thicknesses (in the range of 2–50 nm) and in multi-layered mixed structures with barium fluoride (BaF2) films. The obtained results indicate that non-continuous films are required to minimize the work function (down to 2.7 eV at room temperature), thanks to the formation of surface dipole effects between crystalline islands and substrates, even if the stoichiometry is far from the ideal one (Sc/O = 0.38). Finally, the presence of BaF2 in multi-layered films is not beneficial for a further reduction in the work function. [ABSTRACT FROM AUTHOR]

Pulsed laser deposition operated by an ultra-short laser beam was used to grow in a vacuum and at room temperature natively nanostructured thin films of lead telluride (PbTe) for thermoelectric applications. Different percentages of silver (Ag), from 0.5 to 20% of nominal concentration, were added to PbTe deposited on polished technical alumina substrates using a multi-target system. The surface morphology and chemical composition were analyzed by Scanning Electron Microscope and X-ray Photoelectron Spectroscopy, whereas the structural characteristics were investigated by X-ray Diffraction. Electrical resistivity as a function of the sample temperature was measured by the four-point probe method by highlighting a typical semiconducting behavior, apart from the sample with the maximum Ag concentration acting as a degenerate semiconductor, whereas the Seebeck coefficient measurements indicate n-type doping for all the samples. The power factor values (up to 14.9 µW cm−1 K−2 at 540 K for the nominal 10% Ag concentration sample) are competitive for low-power applications on flexible substrates, also presuming the achievement of a large reduction in the thermal conductivity thanks to the native nanostructuring. [ABSTRACT FROM AUTHOR]

A four-step methodology for the valorization of polysaccharide-based materials into bifunctional heterogeneous catalysts, active in the conversion of CO2 and epoxides into cyclic carbonates, is presented. The synthesis protocol consists of (i) pyrolysis of the starting material to produce biochar; (ii) oxidation to increase the number of –OH and –COOH functionalities; (iii) anchoring of (3-aminopropyl)triethoxysilane (APTES) on the surface of the oxidized biochar; (iv) quaternarization of the amine groups into alkylammonium iodide salts. The versatility of the method was demonstrated by applying the same protocol to six different polysaccharidic materials and wastes: six catalysts with no appreciable differences in terms of chemical composition and catalytic activity were obtained. The bifunctionality given by –OH and ammonium iodide groups was confirmed by several analyses performed on the catalysts. An extensive characterization (elemental analysis composition, FTIR, Raman, SEM, XPS and porosimetry) was done on all the functionalized biochars for every synthetic step. The catalysts were widely investigated in their activity for the conversion of CO2 and epoxides into cyclic carbonates, demonstrating to be effective under mild conditions (3 bar of CO2; 70 °C; 7 h). TONs and TOFs were calculated for each catalyst and condition. Yields up to 96%, with >99% selectivity, were obtained for terminal epoxides. The recyclability of the bifunctional heterogeneous catalysts was also confirmed over five cycles. [ABSTRACT FROM AUTHOR]

Nowadays, there is a dramatically growing demand for nanocomposite materials with new functionalities for their application in chemical gas sensors and other catalytic devices. Moreover, green synthesis methods are intensively employed in the preparation of semiconductor nanostructures to reduce the hazardous effects on human health and the environment. Here the fabrication of a nanocomposite material based on WO3 and TiO2 (WO3/TiO2) with unusual electronic band alignment and novel gas sensing properties is reported. The material is synthesized by an eco‐friendly process based on the water vapor‐induced oxidation of tungsten/titanium metallic films. The pristine WO3 is highly sensitive to acetone, where the response of the material is enhanced by its operating temperature. Instead, WO3/TiO2 composite shows principally different sensing performance and it has a good selective response to carbon monoxide at a relatively low operating temperature. The obtained results indicate that the significant differences between the functionalities of pristine WO3 and WO3/TiO2 material can be attributed to the band alignment and the direction of charge transfer in the WO3/TiO2 heterojunction. Hence, an efficient way for the development of WO3/TiO2 nanocomposites, which can be useful for the engineering and optimization of gas sensing and catalytic properties of WO3, is presented. [ABSTRACT FROM AUTHOR]